INTRODUCTION The present note is the result of an investigation into the correct date of publication of the third volume of A. Seba's great work "Locupletissimi rerum naturalium thesauri. ..". In my own studies on Crustacea I accepted the year 1761 as correct, following in this Engelmann (1846) and the title page of the copy of Seba's book that I consulted. Dr. M. Boeseman, ichthyologist of the Rijksmuseum van Natuurlijke Historie, pointed out to me that in ichthyological literature the year of publication of this volume is practically always cited as 1758. Also Engel (1937) in his biography of Seba gave this later date. In trying to straighten this question out I obtained the most cordial help from Dr. Boeseman, Prof. Dr. H. Engel, former director of the Zoological Museum of Amsterdam, and from Mr. P. Tuyn, librarian of the Amsterdam Zoo, all of whom I like to tender my best thanks. The result of my efforts was rather unexpected, as it proves that neither 1758 nor 1761, but 1759, is the correct year of publication of volume III. The dates of publication of the other volumes have never given rise to any controversy and are always correctly cited. It was thought to be of interest to give here also all the information known to me dealing with the set-up of Seba's work, its authors and artists and the history of its publication. Most of the details are taken from Engel's (1937, 1961) publications on Seba, which form the most important sources on Seba's life, work and personality. I have added a note on the dates of publication of the little known 18271831 French re-issue of the plates of Seba's work, the so-called "Planches de Seba".