A Modern Approach to Classical Guitar: Level 1
This is my go to guitar method book. I use this all the time with my students and I couldn't recommend it more.
A Modern Approach to Classical Guitar: Level 2 & 3
This is levels two and three. This series is such a gem that I think every developing classical guitarist should have this on their book shelf and every teacher should, at least at some point, use this with their students.