6(Educational Piano Library). The All-In-One Piano Lessons Books A, B, C, and D combine selected pages from the original Piano Lessons, Technique, Solos, Theory Workbook, and Practice Games into one easy-to-manage book. Book C is the equivalant to the first half of Book 2. A perfect choice for beginning group or private instruction, the book with online audio offers students a variety of styles and moods, and includes the "best ever" teacher accompaniments. The audio files are accessed online using the unique code inside each book and include a variety of playback tools to assist with learning and practicing each piece.