These aren't flashy books. Each slim volume in The Celebration Series contains a number of clearly-printed piano pieces for student playing—no instructional text, no illustrations, nothing to distract from the business of strengthening and expanding one's keyboard skill. Because they aren't inflated with too many pieces, teachers can familiarize themselves with the material easily and quickly before guiding students through each piece.
Many of the pieces are lesser-known alternatives to the typical teaching "standards"; the first three levels (Preparatory Piano Repertoire-Piano Repertoire 2) are particularly good in this regard, consistently introducing new techniques and teaching opportunities. Baroque, Classical, Romantic and 20th century pieces are all included, offering a range of styles and therefore a range of skills.
Long and short pieces are included, including some "showy" compositions suitable for student performances. Presentation is clean and well-organized and the books are easily propped open so you don't have to struggle to read each line. These are not self-directed courses—students will need guidance as these are collections of skill-suited pieces, not a comprehensive piano instruction program.