As I'm sure you have read in my previous blog A Short History of Walkers, they are an essential part to any military's war machine, particularly where the presence of enemy defensive shields is likely. Now that you've read up on the history and utility of military walkers, I'll get into the meat of the article I intended to write in teh first place; a catalogue of all known military walkers seen in SW from AotC onward. Note that much of this is my speculation, but it is all based on what I have observed in the SW continuity and simple, rational thought. So here it goes:

When Jedi Master Sifo Dyas contacted the Kaminoans and placed an order for a Clone Army for the Galactic Republic, he left out many specifics. He did not even select a template for the clones or suggest a manufacturer for military vehicles. When no such specification is made, the Kaminoans turn to relatively nearby Rothana Heavy Engineering (RHE), a Kuat Drive Yards (KDY) subsidiary, to make the heavy machinery. As such, most of the Republic Army's equiptment came from this company, until KDY picked up most of the contracts in full in order to create massive numbers of such vehicles.

Devoid of specifics from the Republic, the Kaminoans ordered fighting vehicles of every type, and RHE would spend years developing prototypes for dozens of designs, including many walkers.

AT-TE: Aiming to finish a walker which was capable of filling out many roles in the battlefield, from anti-personnel, to anti-vehicle, to medium troops carrier, the All Terrain Tactical Enforcer (AT-TE) was one of the first type to be mass produced by RHE. The AT-TE, was a hexapedal design, which, although primarily developed as an anti-tank walker, was also more than capable of taking on enemy infantry, as well as carrying 20 troops of its own. It was the premier front-line walker for the Republic, and used in nearly all major battles of the Clone Wars. Once the Wars ended, and the Republic morphed into the Empire, large scale battles were rare, and many AT-TEs were decommissioned as their utility shrunk. only a few thousand remained in the Imperial military by the time of Palpatine's death.

AT-XT: Another early member of the Republic military, the All Terrain EXperimental Transport (AT-XT) was an early bipedal walker. What was "experimental" about it? Well, most likely it's gyro-balancing system, allowing it to have a more advanced, upright avian gait compared to the simian one of many droids or the awkward, hunched stance of the AT-PT. The AT-XT was fully capable of front line combat, having twin mortar launchers in addition to its laser cannon, and elite modles contailed shield generators similar to those used by the CIS' Droidekas. Although considered rare, they must have been made in at least the thousands, as they competed is many campaigns accross the galaxy. A number of the AT-XTs were retained by the Empire, although probably under a different name.

AT-AT: First developed early in the Clone Wars, as nearly impervious troop transports and siege platforms, the All Terrain Armored Transport (AT-AT) was one of many prototypes that came out of RHE's thinktanks. With a quadrupedal stance and thermally superconducting armor, only powerful warheads and high-yield beam weapons can penetrate its hull. However, it is vulnerable to small squads of infantry equipped with grapples and explosives, and as such is not often used as a front line vehicle in large scale combat. The AT-AT design was mothballed after the end of the Clone Wars, only to be resurrected a decade later by Colonel Maximillian Veers, who reworked the design and re-implemented them into the Imperial military. As large-scale confrontations became less and less common, the need for heavy combat walkers diminished, and the AT-AT came into the forefront, becoming the most common large walker seen among Imperial forces.

AT-HE: The All Terrain Heavy Enforcer (AT-HE) was developed in the later months of the Clone Wars, as a heavy assault, front-line vehicle of destruction. As an "Enforcer" rather than a "Transport" is was heavily armed with a wide variety of weaponry, unlike the contemporary AT-AT which was equipped with only forward facing armament. The AT-HE ,moat likely had a hexapedal design, and was at least the size of the AT-AT, with all the armor that went along with the design and a contingent of soldiers. As the walker was the equvilant of the A6 Juggernaught, it could take on most any enemy and expect to survive. Most of these behemoths were decommissioned by the Empire as the need for them diminished. The AT-HE has yet to be depicted in visual form, and only written descriptions exist.

AT-PT: The main combat walker of the Republic security forces before the Clone Wars, the All Terrain Personal Transport (AT-PT) was a bipedal design from KDY. It was manufactured after the Stark Hyperspace Conflict, but never saw major production. Much of the original fleet of AT-PTs was lost when the "Black Fleet" of Dreadnought-class Cruisers dissappeared into hyperspace. AT-PTs saw some limited production in the Clone Wars, and were used as mechanized infantry units to great effect. The Empire also mantained a modest force of AT-PTs.

AT-AP: Due to the successes of the AT-PT and the need for a medium assault walker with mosre versatility than an AT-TE, the Republic ordered into production the All Terrain Attack Pod (AT-AP). Nearly four times the size of the AT-PT and holding far more weaponry, the AT-AP was swift on the battlefield, and could deliver a payload nearly as powerful as the heavier AT-TE. Although a bipedal design, a third tri-pod leg must be distended for the fireing of the mass-driver mounted on the face of the walker. Used on front lines across the galaxy late in the Clone Wars, the AT-AP saw continued use in the Empire, as more and more AT-TEs were retired after major conflicts ceased throught the Galaxy.

AT-ST: Late in the Clone Wars, the Republic sought more and more walker designs, which could be utilized to fill the niche of repulsorlift vehicles for when shields hampered their hovering cousins. Taking several design innovations from the AT-XT, KDY developed the All Terrain Scout Transport (AT-ST) to serve as a light assault walker, used in rear-guard action, anti-infantry duty, agressive reconaissance and escort for larger walkers. Although it held a smaller payload than the AT-XT, it housed more versatile weapons, and greater speed. The AT-ST quickly spread through the Republic ranks and would become the premier light assault walker in the Empire. Several variations of the AT-ST were created, including a heavier Assault version, on a par with the older AT-AR.

AT-RT: Designed alongside the much heavier AT-ST, the All Terrain Reconaissance Transport (AT-RT) was designed for light recon duties in terrain where speeders were stifled, mop up action, and police work. Not capable of fighting on a front line, or even in battle formation, the AT-RT was only armed with a single blaster cannon, and the pilot was exposed to enemy fire. Used on many worlds as security and patrol vehicles during the Clone Wars it continued this duty well into the Empire.

AT-AR: Another bipedal walker designed at the end of the Clone Wars, the All Terrain Advance Rader (AT-AR), was larger and heavier than the AT-ST and better equipped to take on enemy armor. While far lighter than the AT-AP, it was an excellant choice for swift attacks against enemy fortifications and more functional in large battle than the AT-ST or AT-PT. AT-ARs would supplant AT-STs across the Empire in later years. The AT-ARs would begin to be phased out in the later years of the Empire in favor of AT-ST/As, although they would remain a common sight on many Rim worlds.

AT-AA: Another craft which first saw development in the late stages of the Clone Wars was the All Terrain Anti Aircraft (AT-AA). This squat quadruped housed a battery full of anti-aircraft rockets and missiles. Although it carried a large payload, it was poorly defended against ground attacks,having no blaster defenses, and no onboard troops it needed escort from dedicated armor and infantry to survive most combat scenarios. Frecuently deployed on battlefields across the galaxy, the AT-AA saw continued use in the Empire, defending convoys traveling through potentially hostile territory.

AT-OT: This octopedal transport walker, the All Terrain Open Transport was a troop transport and cargo carrier used in the Clone Wars. Not designed for front line combat, but for rear-guard, and convoy duties, the AT-OT holds over 30 troops on its dorsal side. These vehicles were well defended against ground assaults, but lacked any sort of air defense, and needed heavier or more specialized walkers to escort them through hostile territory. In the Empire, these would be phased out for a more heavily armored type of cargo walker, based off the AT-TE hexapedal design.

UT-AT: A very interestingly designed walker, the Unstable Terrain Artilliary Transport (UT-AT) was a walker which also had powerful repulsor lift fields to allow it to glide acorss the landscape. These abilities allowed it to scale ner sheer drops and handle unstable landscapes with ease. These innovations would later be implemented in the MT series of walkers during the Empire. Used as a medium assault walker to complement AT-TEs, the UT-AT was a common sight late in the Clone Wars. Its excellent performance led it to see continued production in the Empire, though the lack of need for them led many to be decommissioned.

SPHA: During the Clone Wars, when mobile artilliary was often needed instead of fixed emplacements, RHE developed the Self Propelled Heavy Artilliary (SPHA) units. These large dodecapedal walkers mounted massive artilliary pieces of great variety on their dorsal side, including heavy turbolasers which could pierce Capital Ship's shields in an instant, ion cannon, warhead launchers, and anti-vehicular cannon. It also maintained anti-personnel cannon mounts and held a platoon of soldiers. As the SPHAs reactors could only power a limited number of shots, they often needed to be hooked up to a ship's reactor if continuous use was needed. As the Empire consolidated its control of the galaxy, SPHAs were decomissioned in favor of fixed batteries, but some SPHAs and updated designs saw some use.

SPMA: Developed after their heavier cousins the SPHA units, the Self Propelled Medium Artilliary (SPMA) units saw use in the Empire as the Heavy units were phased out. Although not as powerful as their predecesors, being medium artilliary rather than heavy, these octopedal walkers were smaller, and faster than their predecessors. Like the SPHA units the SPMAs could be fitted with a variety of artillairy pieces (see SPHA entry), and a number of anti-personnel cannon, although they lost much of the SPHAs troop compliment, and had to be escorted by other vehicles. SPMAs also suffered from the same power drawback as the SPHAs in that they could only fire a limited amount of shots in a given time unless hooked up to a more powerful reactor. Still, SPMAs served alongside their behemoth bretheren on worlds which had no dedicated Imperial presence and required the use of mobile artilliary.

AT-AV: The All Terrain Attack Vehicle (AT-AV) is a very little known walker, but its posture is similar to that of the predatory house pet known as pittas. Most likely a bipedal design, though this is hardly verified. It was likely similar to the AT-HE sans the troop compliment, an soley a heavy weapons platform. It was in use by the Empire well before the Battle of Yavin. No known examples of the AT-AV have been depicted in visuals and little text has been written on it.

MT-AT: Developed by the Empire at an unknown time, the Mountain Terrain Armored Transport (MT-AT) was a heavy assault and transport walker used on especially mountainous terrains and worlds where conventional walkers are stifled and airspeeders cannot maneuver. The MT-AT, though massive, was able to traverse sheer cliffs by virtue of its octopedal design, advanced gyros, and well articulated joints. It was very well armed, and could take on most defensive platforms and infantry. It was produced in limited numbers due to their rare deployment, however, it was invaluable to the Imperial war effort on certain worlds.

MT-ST: Another walker in the MT line, the Mountain Terrain Scout Transport, was a hexapedal design, with all the locomotion abilities of the MT-AT minus the troop complement and with lighter weaponry. It was very effective against infantry and light assault vehicles hinding in caves and outcrops.

AT-C: Designed back in the Clone Wars alongside the SPHA units, the AT-C (All Terrain Cannon) units were based on the standard AT-AT frame, but the storage compartments were done away with in favor of a large cannon. The AT-IC (Ion Cannon) and AT-TC (Turbolaser Cannon) were far lighter than fixed emplacements, or SPHA units, but were very effective against patrol ships and small warships, able to achieve optimal range into low orbit. The large guns quickly ate up the walker's energy and long-term use was inpractical unless the walker was hooked up to a large, powerful reactor. AT-C units were often deployed to garissons on backwater worlds where large, fixed emplacements were not utilized, and were produced in limited numbers in the Clone Wars and Imperial rule.

SPMA Unit Added!!