I’m more than a bit tickled to see that Dover has reprinted an edition of Raymond Smullyan’s First Order Logic. It’s a Dover book, cheap and thin, so you can imagine someone casually picking it up to find out what this “logic” is about. But despite its initially inviting exterior, it’s not a book of baby-logic, and section titles include
The Skolem-Lowenheim and Compactness Theorems for First Order Logic; Gentzen Systems; Gentzen’s Haupsatz; Craig’s Interpolation Lemma and Beth’s Definability Theorem
Contrary to my initial reaction, this is par for the course for Dover, which was founded after Tables of Functions with Formulas and Curves was an unexpected smash hit in the United States.
In general, math and logic books range from expensive to insultingly expensive, so it’s more than a little surprising to see serious (if outdated) books on the subject that are cheap. For instance, I’m sure there are better books on the subject, but I’ve actually had Paul Cohen’s Set Theory and the Continuum Hypothesis recommended to me.