So I am always on the search for new how-to books, reference materials, or just art books. One that I have used often in my sculpting and mask making has been Special Makeup Effects for Stage and Screen: Making and Applying Prosthetics.
It has tons of great articles and a constant reference when I am making any new prosthetics. It has some great sections on mold making, texturing sculpts, life casting, adding hair, and silicone prosthetics. Even if you have lots of experience in the field, or none at all, this book is a must have.
I will try to post one book per week, anything I find myself constantly coming back to.