Lorenzo de' Medici was a key figure in the creation of the Renaissance. An important patron of the arts in fifteenth century Florence, he was also a passionate collector of objects from antiquity and the post-antique period. His activities as a collector are documented in a group of 173 letters, previously unknown and published here for the first time, which provide the most complete picture of a well-known and historically important collector. As revealed in these letters, Lorenzo acquired sculpture to embellish his palace, but his real predilection was for small objects: coins, hardstone vases, and gems. His main source was the Roman dealer Giovanni Ciampolini, whose scandalous behavior demonstrates the gamesmanship of the art market. This book reveals how objects were studied, where they were displayed, the criteria for their selection, and their monetary worth.