vi PREFACE degree for their valuable additions and corrections. Herr Moes, in particular, has taken great pains in comparing the book with his own notes. He may be assured that all his observations will be carefully weighed and that those with which I agree will be utilised in the supplement. Unfortunately, Herr Moes, trusting to the accuracy of his own notes, has too often taken me to task without justification. He complains, for instance, that I have not mentioned the acquisition of pictures by museums (for instance, Metsu 13), or the appearance of pictures in exhibitions (for instance, Jan Steen 694), although these events did not take place till after the section in question was at press, if not actually published. Very often, too, he offers as a correction what I have already said in the text, as, for instance, under Jan Steen 86, 456, 503^, 534, and 716 ; Metsu 161 (which, like 136, came from the Choiseul collection) and Dou 136. I shall perhaps deal elsewhere with the other points in Herr Moes' criticism. Here I shall only touch upon his contention that a catalogue of the pictures falsely attributed in printed works to the masters with whom I deal would have formed one of the most useful sections of the book. As to this I would remark : (1) From the first I intended to describe the genuine works of a master, and not those falsely attributed to him. This lies outside my programme and forms a separate task for those who care to undertake it. (2) A catalogue of pictures falsely ascribed to masters in printed works that is to say, in catalogues of exhibitions, collections, and auction-sales would certainly have increased the size of the book by 40 or 50 per cent, and even more in the case of the great masters like Rembrandt. (3) The first volume of such a catalogue would have caused the present owners of such pictures to feel so much annoyance at
