While there is no single book titled exactly "100 Graded Classical Guitar Studies," the description almost certainly refers to (Technically, the book is usually titled "Solo Guitar Playing: A Classic Guitar Instruction Text" which contains the 100 studies, or his anthology "The Classical Guitar" which functions as a graded collection). Cracks - Drzero
However, the term "100 Graded Studies" is most famously associated with in the guitar community. Virus Mike Exe Grew Up Reading