The Pilot's Handbook of Aeronautical Knowledge (or PHAK, for short) is the go-to book for learning about all of the major topics involved in the aviation world. I recommend reading this book in conjunction with a good ground school course.

As other reviewers have mentioned, this book can be downloaded for free directly from the FAA website. It can also be purchased from several publishers if you prefer a hard copy. You could also print one yourself, but I imagine the ink expended in the process would be more expensive than just buying a bound version.

The PHAK covers the basics of aerodynamics and principles of flight; aircraft systems, instruments, performance and documentation, weight and balance; weather theory and services; airspace; navigation; and aeromedical factors. At times, when additional information is available, Advisory Circulars or the FAR/AIM are referenced as needed.

I highly recommend this text for any student pilots operating out of the US. (It may be peripherally useful to non-US pilots, but certainly discussions on airspace will not be valid outside of the United States.) ( )

Pilot’s Handbook of Aeronautical Knowledge, an official Federal Aviation Administration (FAA) Handbook; provides basic knowledge that is essential for pilots. This updated handbook introduces pilots to the broad spectrum of knowledge that will be needed as they progress in their pilot training. This handbook is useful to beginning pilots, as well as those pursuing more advanced pilot certificates. Chapters include: 1. Introduction To Flying, 2. Aircraft Structure, 3. Principles of Flight, 4. Aerodynamics of Flight, 5. Flight Controls, 6. Aircraft Systems, 7. Flight Instruments, 8. Flight Manuals and Other Documents, 9. Weight and Balance, 10. Aircraft Performance, 11. Weather Theory, 12. Aviation Weather Services, 13. Airport Operations, 14. Airspace, 15. Navigation, 16. Aeromedical Factors, 17. Aeronautical Decision-Making, Appendix, Glossary, and Index. Detailed specialized information with both color and b&w illustrations, easy to navigate.