Concept

The original design of the three primary mobile suits in Mobile Suit Gundam, from left to right: "Gundam", "Guncannon" and "Guntank" The original design of the three primary mobile suits in Mobile Suit Gundam, from left to right: "Gundam", "Guncannon" and "Guntank"
Mobile Suit Gundam was developed principally by renowned animator, Yoshiyuki Tomino, along with a changing group of Sunrise creators who went under the collective pseudonym "Hajime Yatate".
During its conceptual phase, the series was originally titled Freedom Fighter Gunboy or simply Gunboy, because the title included a robot armed with a gun and the target demographic was primarily shōnen. In the early stages of production, there were numerous references to the word "freedom", such as the White Base being originally named "Freedom's Fortress", the Core Fighter as the "Freedom Wing", and the Gunperry named the "Freedom Cruiser". The collective Yatate team combined the English word, "gun", with last syllable of the word "freedom", "dom", to form the word Gundom. Tomino then changed the name to the current title, suggesting that the name Gundam signifies a powerful unit wielding a gun that is strong enough to hold back enemies, like a hydroelectric dam holding back floods.
Most Gundams appear as large, bipedal vehicles controlled by their human pilots in cockpits. Like many of the "mobile suits" (the name for these vehicles, including the Gundam) appearing in the various series, the machine is usually piloted from the torso area with a camera built into the head, transmitting the image to viewscreens in the cockpit, allowing the pilot to perceive the outside world. Some exceptions have been known to mount cockpits on other areas of the chassis (ie. the Psyco Gundam, where the cockpit is located in the unit's head).
While Gundams are non-sentient units, there are some exceptions, depending on the story. In the side-story called Gundam Sentinel, an artificial intelligence called A.L.I.C.E. was specified to have developed its own emotions, wanting to become human at the very end of the story,[3] and in The Blue Destiny, another side-story, four mobile suits (where one of them is not a Gundam) built with the EXAM System, which shares a Newtype human soul, allows them to act accordingly on their own.[4] These are the only canonical and specified plot-related Gundams that contains self-sentience.

Innovation

Mobile Suit Gundam is said to have pioneered the real robot area of mecha anime.[5] Unlike its super robot cousins, Gundam attempts at realism in robot design and weaponry, as well as the thematic and ethical roles of the robots themselves. Zambot 3 was an earlier program by Tomino, where he began developing the ideas in Gundam, and along with Super Dimension Fortress Macross, would form the basis of the genre.
The inherent theme of all the various Gundam series is the harsh depiction of the atrocities of war. All the machines, including the Gundams, are always depicted realistically, that is, they run out of energy and ammunition, they break and malfunction like all machines do. The technology, at least that of the Universal Century, is practical and is either derived from true science, including Lagrange points in space, the O'Neill cylinder as a living environment, or at least well-explained technology that is potentially feasible, and/or requiring only a few fictional elements inserted into real science to function (Minovsky Physics, as a means of energy production from helium-3).
The narrative itself revolves around the emotions of the characters, who are usually thrown into conflict without much choice and faced with the death, destruction and dehumanization inherent in war. With few exceptions (mostly in side stories), there are no absolute heroes and villains; all have their motives, failings, and virtues. Political battles are as likely to determine the outcome of a war, as it often is. Gundam also features debate on various important philosophical issues and political ideals, both historical ones, and some of those likely to crop up in the future. Of particular note are the frequent explorations of the nature and meaning of war, the ideal of pacifism, and the continuing evolution - natural or engineered - of humanity and its consequences. These are often framed in the series as a debate between the protagonist and antagonist over the course of a duel, as they try to convince each other of the righteousness of their causes.
Finally, most of the stories are basically structured as coming-of-age dramas, where the main protagonist (and sometimes the main antagonist) and most of the cast personalities, points of view, and actions may (or may not) change dramatically, as the events on the series unfold. This makes the plot seem more realistic. In early super robot animated series, the hero and cast usually act in the same predictable manner in most episodes, occasionally seeming to have no connection between episodes. In the various Gundam series, the characters' personalities and actions are transformed/developed by the turn of events surrounding them; some achieve their goals, others are hardened by war, and some even switch allegiances (whether for their own agendas, or following their conscience, after a change of philosophy). The best example of this is how the personalities of longtime rivals, Amuro Ray and Char Aznable, are influenced by their experiences in the Gundam saga.
Gundam's realistic scientific setting has gained its reputation in the field, as well. On July 18, 2007, as MIT's Astronautics Department's Professor Dava Newman displays her Biosuit, the normal suit as seen in the Gundam series was referenced as Mobile Suit Gundam's Normal Suit is now real by various news.[6][7] On February 14, 2008, as NASA proposed its beginning of the nuclear thermal rocket engine research, Technobahn, a scientific journal in Japan relates it to the Gundam universe, having wide usage of nuclear thermal rocket engines on its mobile suits.[8]