That was a kingly gift at the time I imagine. I mean the expense of getting them printed and bound couldn't have been cheap. I grant that small books have been around a while though too. Italic was created so that its creator could bring out the first 'pocket edition' of classic books. It also led to the need of 'reading the small print' on contracts.
Most of the 20th century authors that I've read such as Bradbury, Asimov etc. would have used typewriters for writing their books. Piers Anthony in his book "Bio of an Ogre" talks about how he went from a typewriter to one of the early computers.