Using only the True20 classes of Expert, Adept and Warrior you can create all the standard, or at least the d20 3.x standard, fantasy classes. Yes, Wizards in the D&D sense are not the same as True20 adepts, but you can get them there if you have this book. Each class is defined and then progressions from level 1 to 20 are given. Of course, you can stray from the various paths to do your own thing, that a strength of True20, not a weakness. Also, an added feature of these fully stated out level progressions is that if you need an NPC, say a 3rd level bard or a 15th level cleric, then you have those stats ready to go. It doubles as a rogues gallery.