There is another feature connected with them which is of special interest. One man appears to have contributed to all the books thus marked--either the dedication, the preface,[45] or the lines "To the Reader"; in some cases all three. It may be urged in opposition to this view that in those days there was a form in which dedications and prefaces were written, and that this was more or less followed by many writers, but this contention will not stand investigation. There are tricks of phrasing and other peculiarities which enable certain literary productions to be identified as the work of one man. Some of the finest Elizabethan literature is to be found in the prefaces and dedications in these books. The theory now put forth is that Francis Bacon was directing the production of a great quantity of the Elizabethan literature, and in every book in the production of which he was interested, he caused to be inserted one of these devices. He kept the blocks in his own custody; he sent them out to a printer when a book was approved by him for printing. On the completion of the work, the printer returned the blocks to Bacon so that they could be sent elsewhere by him as occasion required. The most elaborate of the AA designs is Figure XII., and the writer has only found it in one volume. It is "Le Historie della Citta Di Fiorenza," by M. Jacopo, published in Lyons by Theobald Ancelin in 1582. "Exact was his correspondence abroad and at home, constant his Letters, frequent his Visits, great his obligations," states the contemporary biographer, speaking of Francis Bacon. It is difficult to arrive at the exact meaning of these words. There is little correspondence with those abroad remaining, no record of visits, no particulars of the great obligations into which he entered. In the dedication of the 1631 edition of the "Histoire Naturelle" to Monseigneur de Chasteauneuf, the author speaking of Bacon writes:--"Le Chancelier, qu'on a fait venir tant de fois en France, n'a point encore quitté l'Angleterre avec tant de passion de nous découvrir ses merveilles que depuis qu'il a sceu le rang dont on avoit reconnu vos vertus." These frequent visits to France are unrecorded elsewhere, but here is definite testimony that they were made. There are good grounds for believing that Bacon was throughout his life, until their deaths, in constant communication with Christophor Plantin (1514-1589), Aldus Manutius, Henry Stephen (1528-1598), and also with Robert Stephens the third (1563-1640). All these men were not only printers, but brilliant scholars and writers. If search be made, it is quite possible that correspondence or other evidence of their friendship may come to light. Be that as it may, there were undoubtedly a number of books published on the continent between 1576 and 1630 which in the sparta upon them bear testimony to Bacon's association with their publication.