Whether you are a singer, speech pathologist, otolaryngologist, scientist or just curious about the voice, this is THE book if you want to know more than just the standard spouting. Ingo Titze defined the word vocology. As both a scientist (Ph.D. in physics) and an operatic tenor, he is world renown and is arguably scientific world leader over the last several decades in the study of the voice; his full bio is at the National Center for Voice and Speech (NCVS) website. They sell this book at that site.
The book is well written. It starts from the basic anatomy and physiology, moves to basic principles of physics and acoustics, and ends with common voice disorders.