When last year I returned to Florence for a long stretch of work, I was overwhelmed by the amount and completeness of the material preserved in the Archives and in the Libraries, though previous experience should have prepared me for what I would find. One becomes strikingly aware of the spottiness with which the material of the Archives has been used in our histories of the Renaissance, and one begins to feel rather critical of the trend in present Renaissance literature towards basing new theories on reinterpretations of the material which nineteenth century historians discovered, instead of turning to the wealth of unused source material. Hardly a day passes when one does not leave the Archives either complaining about the fact that a fundamental source —on whose deciphering one scholar after the other has to spend precious time—remains unpublished, or filled with suggestions for work which ought to be undertaken.