In the Low Countries, and particularly in Holland, the operations of the censors and Index-makers of Italy, Spain, and France constituted a factor of not a little importance in furthering the development of the book-trade. The printer-publishers of Holland kept themselves promptly informed of the operations of the various authorities which had taken upon themselves the task of supervising the literature of the world. Early copies of all the original Indexes found their way, as soon as produced, to Leyden, Amsterdam, and Utrecht, and were promptly utilised by the enterprising Dutch publishers as guides for their publishing undertakings. Within a few months of the time when the censors of Rome or of Paris had completed, as they supposed, the cancellation of the local editions of the condemned books, copies of the Holland issues would begin to find their way, more or less surreptitiously, into the hands of the readers of the country of origin. Literature is, in this respect, like water; whatever the intervening obstacles, it is pretty sure to find its level, or, like air, to find its way under the pressure of the mass of the intellectual atmosphere to the points where there exists an intellectual vacuum or need. It is certain that at a time when, in the absence of journals, there were but limited means of information as to the existence or the character of literary productions, the Indexes proved to be most serviceable guides concerning books for which communities were waiting. The restrictions and prohibitions of the censorship system brought serious and sometimes crushing difficulties upon publishing undertakings in certain centres, but proved of invaluable service as suggestions for active-minded readers throughout Europe, and also for the undertakings of publishers in countries like Holland, who, free from restrictions at home, were very ready to utilise their presses for the profitable work of distributing abroad literature for which the Church, in advertising it as heretical, had taken pains to prepare the way and to provide a public. However great were the difficulties brought through the Church censorship upon the book-trade in other communities, it was certainly the case that for the printer-publishers and book-distributors of Holland it secured very direct and considerable advantages.