Federal Aviation Administration 
Pilot’s Handbook of Aeronautical Knowledge [PDF ebook] 
FAA-H-8083-25A

Used extensively as a reference source for the FAA Knowledge Exams, this resource includes basic knowledge that is essential for all pilots, from beginning students to those pursuing advanced pilot certificates. This updated guide covers a wide array of fundamental subjects, including principles of flight, aircraft and engine structures, charts and graphs, performance calculations, weather theory, reports, forecasts, and flight manuals. Required reading for pilots for more than 25 years and formerly published as an Advisory Circular (AC 61-23C), this new edition is now listed as an official FAA Handbook.