  His logical interests veered sharply while he was writing The Craft. To sixteen chapters on the logic of categoricals, hypotheticals, terms and relations, he added, almost as an afterthought, one on modal logic and one on the axiomatic method. Prior finished the manuscript in December 1951 and sent it to the Clarendon Press; fourteen months later they wrote agreeing to publish the book if Prior would both shorten it and give greater emphasis to modern logic. He undertook to make the changes, but ended up writing a completely different book. This was finally published in 1955 with the title Formal Logic; it ran into a second edition in 1962.