While many details have been preserved of the business history of the Elzevirs, I find no reference to their books of account, and no record of manufacturing expenditures such as has been preserved of the Antwerp publisher, Plantin. I have, therefore, been unable to ascertain what payments were made to the home authors like Descartes, Grotius, Heinsius, and others, of whose works repeated editions were issued. As these later editions were in the majority of cases revised by the authors themselves, it is evident that they must have been published under some satisfactory arrangement. It would also have been interesting to ascertain what remuneration was paid for editorial service, especially in such undertakings as the great series of Classics, for translations, for the work of press supervision, and for the service of literary counsel, of which the Elzevirs secured from scholarly associates a very full measure. But the data for such information are not available. There is a similar lack of information concerning the success or the lack of success of the different publishing undertakings. We can only conclude from the fact that so large a proportion of the books printed reached later editions, in some cases being reprinted five or six times, that for these works, at least, a continued and a remunerative sale was secured. The references in the correspondence from different parts of Europe give evidence that the most important of the undertakings of the House, the series of Latin and Greek Classics, had won for itself a favourable reception with students and scholars in far distant educational centres, and it is evident that the total sale of these volumes must have been very considerable. There is also what might be called the negative testimony to the general success of the publishing judgment of the Elzevirs, that there is record on their long list of no single undertaking of importance which proved a burdensome failure, as was the case, for instance, with the great Bible of Plantin. It was certainly the case that the thorough organisation of the bookselling business of the House, an organisation which included connections not only throughout the Netherlands, but with the principal book-centres of Germany, France, Scandinavia, and Italy, gave them in the work of finding a market for the output of their presses, a very material advantage over the firms whose business was limited to printing and publishing. The catalogues issued by the several retail concerns carried on by the Elzevirs were by far the most comprehensive, the best classified, and in every way the most complete that had as yet been known in the book trade, and these catalogues served as models for the trade bibliographies of the succeeding half century.