The _Opera nova contemplativa_ was from one point of view a mere survival, but Vavassore is not likely to have produced it solely to cause twentieth century antiquaries surprise. He must have had a business reason for having recourse to block-printing, nor is that reason very hard to find. From the frequency with which the early printers changed and recast their types, and the short intervals at which popular books printed with types were set up afresh, it is clear (1) that the type-metal[5] employed was much softer and less durable than that now in use, and that only small impressions[6] could be taken from the same setting up; (2) that only a small amount of type was cast at a time, and that type was quickly distributed and used again, never kept standing on the chance that another edition would be wanted. Now when we come to the illustrations in printed books, we find the same woodblocks used for five or six successive editions, and then, in many cases, enjoying a second lease of life as job-blocks, used at haphazard by inferior printers. It is clear, therefore, that while it was a much more difficult and laborious business to cut the letterpress of a book on blocks of wood than to set it up with movable types, when the blocks were once made much more work could be got out of them. In a word, in the case of a small book for which there was a steady demand, a printer might be tempted to have it cut as a block-book for the same reasons as might cause a modern publisher to have it stereotyped. The labour of cutting the letterpress on wood was much greater than that now involved in stereotyping, and the result clumsier. Hence it was only to short books intended for unexacting purchasers that the process was applied and with two or three exceptions it was used only for illustrated books with a small amount of text. But within this restricted field it had its own commercial possibilities, and there is thus nothing surprising in its coexistence with printing from movable type.