re: Books on Vocal Technique
It's not really an instructional book, but "Great Singers on Great Singing" by Jerome Hinds is a collection of interviews lead by the great operatic bass in which other opera singers tell of their technique, daily routine, etc. Hines even speaks with noted vocal coaches and a speech therapist, so you have some medical insight, too. I would say it's absolutely essential reading if you're taking voice lessons of any kind ... And it's pretty cheap!