From the introduction:
Everyone loves options, especially in Dungeons and Dragons where character building is half the fun of the game and this is what the Power Packs are about: Options.
This power pack for Fighters introduces a slew of At-Wills, Encounter, Utility, and Daily powers. All of these powers are designed to work with existing builds and also help shape out the game where the Fighter may be lacking in a particular play style.
These powers will allow you to play the Fighter how you want to play them!