The brilliantly expressive clay models created by Gian Lorenzo Bernini (1598-1680) as sketches for his works in marble offer extraordinary insights into his creative imagination. Although long admired, the terracotta models have never been the subject of such detailed examination. This publication presents a wealth of new discoveries (including evidence of the artist's fingerprints imprinted on the clay), resolving lingering issues of attribution while giving readers a vivid sense of how the artist and his assistants fulfilled a steady stream of monumental commissions. Essays describe Bernini's education as a modeler; his approach to preparatory drawings; his use of assistants; and the response to his models by 17th-century collectors. Extensive research by conservators and art historians explores the different types of models created in Bernini's workshop. Richly illustrated, Bernini transforms our understanding of the sculptor and his distinctive and fascinating working methods.