Regarding the Shearer books....there are actually two distinct sets of his work. The Mel Bay books, "Learning the Classic Guitar" (Parts 1, 2 and 3) are what most here refer to as "the Shearer books". There's lots of great, valuable info, but the learning experience is disjointed; Book 1 is all about the physical aspects of the guitar, and is meant to accompany Book 2, where actually learning to read music and playing occur. No problem if you have a teacher. The books were designed and intended to accompany individual instruction with a teacher. Big problem if you're trying to learn on your own. There's no learning path or road map.
The Shearer Method books published by Alfred a few years ago, represent Aaron Shearer's magnum opus. Shearer finished the manuscript shortly before his death in 2008. Thomas Kitka and Alan Hirsh finish the three volumes and brought them to market: Classic Guitar Foundations (Book 1), Classic Guitar Development (Book 2) and Learning the Fingerboard (Book 3).
Although the Shearer Method books are clearly targeted to classroom teaching at the secondary school level, I find they are quite suitable for self-study as well. Each book comes with a DVD containing instructional video, as well as audio files and audio software to play the files at slower and faster speeds. Moreover, there's a robust amount of supplementary material, both text and video instruction, that allows the authors to provide more in-depth material than allowed in the book. The material is made freely accessible and appears to be updated regularly.
The Shearer Method books can be seen as a careful, methodical and thoughtful "integration" of the previously published "Learning the Classical Guitar" books. Refreshingly, the music in these books is mostly original and musically interesting. The biggest advantage the Shearer books have over other methods out there (Noad, Parkington, etc.) is the extensive and integral use of technology to assist with the teaching and learning process. The pace may be too slow for some. Skills learned in previous lessons continue to be drilled in later lessons while new skills are introduced. I prefer this approach. I shows a thoughtfulness to develop players who are confident and secure in their technical and musical skills, providing a solid foundation for future musical development. However, I do appreciate that some may find this approach repetitive and risks boring the student, making them feel they aren't progressing fast enough.
To be sure, the Shearer Method books present a modern approach to teaching classical guitar. And the prescribed learning path may or may not resonate with you or your teaching style. But these books are worthy of serious consideration, especially for self-learners and those without regular access to a teacher.