I'm sure this topic has been discussed somewhere in the past, but I have a voice student who needs to learn theory from the ground up. I often use Alfred's Essentials of Music Theory Books 1&2 (3 usually gets more into theory that really doesn't apply to voice students unless they plan on majoring in voice in college). What other theory books out there do you use that might work well for general music theory?

My sisters actually use Keith Snell's Fundamentals of Piano Theory with their violin students. It helps the students to have a knowledge of bass clef and harmony that they miss otherwise.

For non-keyboard books, try the Frederick Harris publications. I personally like the Sarnecki books for layout and clarity. These books are designed for the conservatory theory exams which are not instrument specific. They can be quite intense, however. You would end up with very smart vocalists.

I used Barbara Wharram's Elementary Fundamentals of Music which is the bible for all three levels of the RCM rudiments exam. It introduces themes such as notation, time, key signatures, intervals etc. in separate chapters at a "P" (preliminary) level which goes with the preliminary exam. Then after doing the tests at the back of the book you go through the same chapters again at the "1" level (gr. 1, intermediate), and if you wish you can then go the *2* (advanced level). At that point you are using C clefs, transposing from transposed instruments and various kinds of scores and small exercises with cadences. This thread (top) sample page shows part of one of the last pages in the book. It is a dry, illustration-free, compact book of almost 300 pages. It begins with learning where the notes are and what a staff is.