After a long hiatus, I returned to drumming about a year ago. Although the basics of tuning came back quickly, I never REALLY learned to tune well when I was younger. In reading a variety of drum-related books I have come across many approaches to tuning. Most of these methods were too simple to produce the results I sought. As I continued my search I did come across an excellent web site "Prof Sound's Drum Tuning Bible v3" (http://home.earthlink.net/~prof.sound/) which I suggest to anyone serious about tuning. This web site contains even more information than Schroedl's book but it provides no audio reference files (not critical but very helpful) and the approach to tuning is really more than I am willing to undertake regularly. The information on this site did, however, allow me to achieve the sound I sought.
Searching for a simpler approach, I ordered Schroedl's book. This book presents a simple, straightforward approach that gets the job of tuning done effectively and efficiently! The audio files are helpful (some more than others) and serve to clearly demonstrate what is written. I can now get my drums sounding just the way I want and do it quickly. Thanks to this book, I spend more time playing and less time fiddling with my drums. I highly recommend the book.