Helpful, but somewhat technical
James C. McKinney's "The Diagnosis and Correction of Vocal Faults" is a useful overview of the function of the singing voice and the major pitfalls that students often face. Although the explanations are detailed and thorough, some prior knowledge of terminology (including anatomy) is probably necessary for full understanding.
The chapters on vocal classification and registration are interesting, but rather abstract. However, the quick method of determining choral vocal parts is useful. Very few exercises are provided; McKinney suggests types of approaches to deal with specific issues.
This book is perhaps most useful for choir directors and voice teachers with some basic understanding of vocal terminology. It would also be helpful for singings seeking to understand their own voices better, but it is not a "self help" book for them.
