If you're asking about the published books that they send you -- it's ASA oral preps, PTS, Jepp Instrument/Commercial, Instrument Flying Handbook, Instructors Handbook, Turbine Handbook, Mutli Flying Handbook, Gleims written test preps -- pretty much every book that you'll need.
If you're asking about the Seminole supplement and checklists, I believe they're written by ATP's Chief Pilot, Rich Tillery.