It seems only yesterday that the fourth edition came out: but — as I found in the CUP bookshop today — there’s now a fifth edition of Computability and Logic. The preface announces that the main revision in this addition is a “simplification of the treatment of the representability of recursive functions”. And the material on Robinson Arithmetic has been rewritten, and there’s a more explicit discussion of the two uses we can make of Church’s Thesis (essential and eliminable).
I confess to still perhaps preferring the more spartan elegance of the early editions. And I think that the book has always been, then and now, rather harder for students than the authors intended (which was one reason that I imagined that there was room for my Gödel book, even though it criss-crosses over quite a bit of the same territory). But credit where a great deal of credit is due: this is still a lovely book, full of good things and with some terrific explanations of tricky stuff. So hasten to your bookshop …
Comparing the two tables of contents, the structure seems the same.
I felt very strongly that the death of Boolos and the introduction of Burgess diminished the elegance of it a great deal. Is there any sense that the structure of the fifth edition is better than the fourth?