There are several FAA handbooks and manuals that are must-haves when preparing for your FAA knowledge exam or checkride.
WEIGHT-SHIFT CONTROL AIRCRAFT FLYING HANDBOOK
The FAA WEIGHT-SHIFT CONTROL AIRCRAFT FLYING HANDBOOK introduces the basic pilot knowledge and skills that are essential for piloting weight-shift control trike light-sport aircraft. It was written specifically for weight-shift control trikes by industry expert Paul Hamilton and covers topics never before known or published. This is the Bible for all trike pilots and trike instructors.
WEIGHT-SHIFT CONTROL AIRCRAFT PILOT’S HANDBOOK OF AERONAUTICAL KNOWLEDGE

ASA FAR/AIM
The most pertinent FAA regulations for pilot, combined with the Airman’s Information Manual AIM. The BIBLE of FAA regulations and operating procedures for all pilots and aircraft, plus specific regulations for weight-shift control trikes. This is the basis of all questions and essential for the checkride.
ASA PRACTICAL TEST STANDARDS - SPORT PILOT
The FAA Standards for which every pilot and Flight Instructor is tested for the checkride.