The Pilot's Manual: Ground School: All the aeronautical knowledge required to pass the FAA exams and operate as a Private and Commercial Pilot

The Pilot's Manual: Ground School: All the aeronautical knowledge required to pass the FAA exams and operate as a Private and Commercial Pilot (The Pilot's Manual Series)

Pilot's Handbook of Aeronautical Knowledge: FAA-H-8083-25B (FAA Handbooks series)

Airplane Flying Handbook FAA-H-8083-3C: Pilot Flight Training Study Guide (Color Print)