Historically the works of Andrea del Verrocchio have not been given sufficient attention. A number of influential artists, most notably Leonardo da Vinci, were among his students. This dissertation addresses the problem of Verrocchio's teaching methods and techniques, particularly the use of sculptural models, to determine the degree of stylistic and technical influence he had on his students. The examination of contemporary sources and documents, cultural and art historical studies, technical data from restorations and laboratory inspections, direct visual analysis (connoisseurship) and photography of many of the artworks produced in this workshop were used to develop the thesis. Many of the conclusions in this study are based on the relationships of selected drawings and paintings to particular sculptures. Further support for the findings are made evident in a series of images derived from photographs run through a morphing program on a PC. Among the most important findings to have been proven through this study is that the stucco Bust of St. Jerome in the Liebieghaus, Frankfurt, was used as the model for the Bust of St. Jerome in the Palazzo Pitti, Florence and for the head and neck of St. John in Verrocchio's Baptism of Christ in the Uffizi Gallery, Florence, and that the perspectographic device described and illustrated by Leonardo was employed in its production. This evidence demonstrates that Verrocchio was cognizant of the technique and that the published date of c. 1500 for the Liebieghaus bust is incorrect by at least thirty years. It is also argued that an attribution to Leonardo for the painting of the Bust of St. Jerome in the Palazzo Pitti, Florence, be accepted. The criteria used here are also applied to a Madonna and Child with Two Angels in the National Gallery, London. The attribution of these these two tempera paintings to Leonardo opens a new discussion on his early training, as all previously accepted paintings by him are in oils. These findings have led to a number of other attributions and re-attributions of works to various members of Verrocchio's workshop.