The "Music Theory and Practice" is compatible with the current international literature and is adapted to the Greek reality. It is intended for the student or philomusian without previous theoretical training, who wants a productive knowledge of the basic terms, symbols, concepts and functions of music theory. It is the methodical and flexible textbook for music theory classes of all schools: Conservatories, Music Schools, Training Institutes and Higher Education Institutions. The series "Music Theory and Practice" consists of 3 volumes, the first volume which mentions the theory and the second and third with the exercise books. Chapters 1, 2 & 3 examine the fundamentals that shape music: notes, rhythm, and expression, while Chapters 4, 5, and 6 examine the relationships that develop between musical sounds: intervals, scales, and the chords. A special report sets out the rules of musical notation, classifies musical instruments and records the scales of Greek traditional music. The methodology suggested by the author encourages the student to take one step at a time. To start the study from the example and to proceed to the understanding of the concept from the theoretical text. Believing that the acquired knowledge is consolidated with practice, the two volumes of the exercise books contain a number of simple applications and creative problems, while activities of acoustic practice and composition are indicated.