Professor Renzo Canestrari (whose essential biographical notes are summarized) had a scientific activity over almost seventy years. This activity covered various areas of psychology, regarding in particular the psychology of perception, the psychology of developmental age and the clinical psychology. Taken as a whole, his publications reporting experimental and clinical findings and new insights into several theoretical issues constitute a cultural heritage of great epistemological value. Moreover, they document important steps of the development of Italian psychology in the second half of the 1900s, the knowledge of which is potentially of great interest for the history and epistemology of psychological sciences.