The Gradus volumes are products of the last quarter of the twentieth century and represent in many ways a summation of styles and techniques that had been introduced by composers during the previous fifty years. In his preface, Adler notes that “the co-existence of many diverse styles and techniques is one of the significant characteristics of twentieth-century musical composition” and explains that the purpose of these volumes is to expose “the ear as well as the fingers of the student to the demands of the present and the immediate past.” He goes on to say that “each short exercise utilizes a technique of composition which has become common practice in the last half-century. The compositional devices used are discussed in the notes, which also include suggestions for further independent application by student or teacher.”

The explanatory notes provided for each piece are models of clarity and of invitation to explore and enjoy the pieces both as compositional illustrations and as musical experiences. They could also form a composition course for student composers.

Book I is at the early-intermediate pianistic level. The explanations are understandable by young students, and the pieces are short, each less than a page (see ex.1.1).

Book II covers the entire “intermediate” range as it is generally understood but leans heavily toward its upper limits with pieces that are longer, technically more difficult, and intellectually more challenging (see ex. 1.2). In several cases they require the student’s creative participation in the formation of the composition. For example, a tone-row square is given, followed by some pieces based on versions of the row, with an exercise to accustom the student to the concept and sound of the original row. Two pieces using famous folksongs are paired to be learned simultaneously before they appear cut apart into seventeen random-order segments for the student to combine aleatorically.