The harmonic ear is the second part of the trilogy Harmonie - Improvisation - Composition This manual is a practical and lively introduction to improvisation sung or played in a tonal context. The works studied range from the classical repertoire to the Blues, passing by the French Song. Harmonic analysis is the basis of improvisation organized, constructed, developed, original. The application exercises accompanied (70 play-back on CD) place the improviser in the most realistic situation possible. As a first step towards spontaneous and original creation, improvisation opens the way to musical composition.