This book is born from the need to fill a gap in the intervalic and harmonic education offered to string musicians. Violin and viola have a literature of etudes and methods designed to cover all the technical aspects of the instrument so extensively that in fact it is almost impossible to seriously approach and work each and every one of them during the formative period. However, despite the large number of methods for violin and viola, there is still a gap in the intervalic and harmonic work for these instruments. With this book you will learn how to play, understand, and connect all the major, minor, diminished, and augmented triads and you will achieve great technical freedom, because these new etudes prepare the modern violist for the current viola repertoire, improving the sight reading and accelerating learning process of new repertoire.