If during one’s work one comes across certain names again and again, names of old collectors, of one’s colleagues in earlier days, who with their private museums laid the foundation of our scientific institutions, one naturally becomes keen on knowing more about them. The results of this curiosity, collected by and by in spare time and sometimes too in time stolen from other more serious occupations, are given here to the public in the hope that they may meet their interest. As to me I thought it a pleasure and certainly worth the trouble. I first collected all that I could find in a casual way and at last I hunted for them more systematically, until the time came that circumstances put an end to it. Incomplete though this list may be, I now send it to the press, hoping that it may give many facts and many sources unknown till now either to historians or to zoologists. When I prepared my biography of Albert Seba I met so many names of old collectors that roused my curiosity that at last I decided to make a list of them, trying to find out what sort of people they were and recording what is known about their collections. It was not easy to put a limit of time to the list, so that finally I included all Dutch collectors I could find up to the present day. If I have omitted some I hope I shall be forgiven, and that readers will provide me with the names of those omitted, that they may serve for a supplement.