Music Theory and Practice is compatible with the current international bibliography and is adapted to the Greek reality. It is appropriate to the student or the music lover who do not possess previous theoretical background but who are willing to obtain productive knowledge of the basic expressions, symbols, concepts and functions of music theory. It is the methodic and flexible textbook for the classes of music theory from all instruction sources: Odeon, Music Schools, Institutes and Foundations for Higher Education. The collection “Music Theory and Practice” is composed of three volumes; vol. 1 contains the theory and vols. 2 and 3 are exercise books. In Music Theory and Practice, vol. 1, chapters 1, 2 and 3 examines basic elements of forming music sound: notes, rhythm and expression, while chapters 4, 5 and 6 consider the relations growing among notes: intervals, scales and chords. A special reference is made to the rules of music notation, rules of organology and specification of the traditional Greek music scales. The methodology proposed by the writer encourages the student to give one new step each time, to start the study from one given example and then to progress towards the understanding of the concept from the theoretical text. With the conviction that the acquisition of knowledge is consolidated with the practice, in the two exercise books are included several simple applications and creative problems, as well as suggestions of activities concerning ear training and composition.