**THE BIG RED LOGIC BOOKS** The headline news — they are open access.

**LOGIC MATTERS BLOG** Peter Smith’s occasional blog posts on logic, music, and other enthusiasms. Most recent posts: ‘Timothy Chow on the NF consistency proof and Lean’ (May 3); ‘Lea Desandre and Thomas Dunford’ (May 4); ‘Two category theory books’ (May 8).

**INTRO TO FORMAL LOGIC**. A corrected version of the second edition of *An Introduction to Formal Logic* is freely available here. There are also links to answers to exercises and to various supplementary materials.

**GÖDEL’S THEOREMS**. Two books are freely available here, *An Introduction to Gödel’s Theorems* and the much shorter *Gödel Without (Too Many) Tears*, along with related materials.

**CATEGORY THEORY** Links to resources at an introductory/intermediate level, including lecture notes and freely available books, and my drafts *Ca**tegory Theory I: A gentle prologue* and *Ca**tegory Theory II: Introducing four basic themes*.

**THE STUDY GUIDE AND BOOK NOTES** You will find here the much-downloaded *Beginning Mathematical Logic: A Study Guide*, its *Appendix* reviewing some of the wider-ranging books on mathematical logic, together with a list of some forty further book notes.

**ARCHIVE** Links to various old blog posts, papers, more reviews and other pieces.

**LaTeX FOR LOGICIANS** Pages pointing to a wide range of resources of interest to logicians, philosophers and others using LaTeX.