The origin of this work was a footnote in an article by Professor A. H. M. Jones on the Roman Civil Service. Since 1955 the footnote has grown into a book and beyond, largely because neither he, as I suspect, nor I certainly, envisaged that the evidence would present itself in quite such formidable quantities or pose such challenging problems of interpretation and presentation. These factors also made necessary a long series of preliminary studies, which in turn have contributed to the long delay in putting this book into definitive form. The nature of the material and of the writing is intractable, and it has become increasingly clear to me that time and effort will not bring much improvement. Hence I have thought it better to present the subject all together as it appears to me now rather than to pursue an unattainable perfection at the cost of an indefinite delay.

This is also an appropriate moment for stocktaking. Until quite recently the Familia Caesaris was an almost totally neglected field, despite its obvious importance for early Imperial social and administrative history, as well as for onomastics. But in the last few years two major studies in particular have appeared by G. Boulvert and H. Chantraine. I have taken this opportunity to point out the areas where progress and agreement can be recorded and where the main problems still lie.