Ingo Titze’s “Principles of Voice Production” is the contemporary vocology bible. The book approaches the major complications of the voice with thorough, mathematical clarity. Topics such as vibrato, oscillation, breathing, the vocal folds, resonance, formants, harmonics, vocal health, registration, and more are explained in scientific detail, proving, where possible, the realities behind the inner workings of this complex instrument, and providing context around ideas that are still in debate. The challenge lies in its mathematical depth. Singers and SLPs who shy away from math and science will find this daunting, if not an outright turn off. If this describes you, then our suggestion is to find the time to attend the Summer Vocology Institute in Salt Lake City in order to be guided through the material with the experts. If you don’t have the time for that, it’s still worth having the book on your shelf, to work through in small doses, as there is simply no more thorough document available.