Martial Study( Tome of Battle: The Book of Nine Swords, p. 31)
[Fighter Bonus Feat, General]
By studying the basics of a martial discipline, you learn to focus your ki and perfect the form needed to use a maneuver. As a result, you gain the use of a combat maneuver.
When you gain this feat, you must choose a discipline of martial maneuvers, such as Desert wind. The key skill for the chosen discipline becomes a class skill for all of your classes (current and future).
Select any maneuver from the chosen discipline for which you meet the prerequisite. If you have martial adept levels, this maneuver beocmes one of your maneuvers known. If you do not have martial adept levels, you can use this maneuver once per encounter as a martial adept with an initiator level equal to 1/2 your character level. If you do not have martial adept levels when you take this feat, and you later gain a level in a class that grants maneuvers known, these new maneuvers can only be used once per encounter and have no recovery method. If you later gain levels in a martial adept class (crusader, swordsage, or warblade), you use the recovery method for maneuvers learned a a result of those class levels, but your previous maneuvers (gained through this feat or through prestige class levels) do not gain a recovery method.
A maneuver learned through this feat cannot be exchanged for a different maneuver if you are a crusader, swordsage, or warblade. Once you choose a maneuver with this feat, you cannot change it.
You can take this feat up to three times. Each time you take it after the first, you gain one of two benefits. You can choose a new discipline, gaining one of its maneuvers and its key skill as a class skill, as described above. Alternatively, you can choose a maneuver from a discipline to which you have already gained access by means of this feat. In either case, you must meet the maneuver's prerequisite. A fighter can select Martial Study as a bonus feat.