What free logic textbooks and study materials are available on Logic Matters?

Updated

Logic Matters, Peter Smith's site, hosts several complete logic textbooks and study guides as open-access downloads, plus a large set of book notes and LaTeX resources for logicians. The free materials cover formal logic, Gödel's theorems, category theory, and a general study guide to mathematical logic. Everything listed below is described on the site as freely available; the site does not state any price, account, or login requirement for these downloads.

The main free textbooks

Resource What it covers Notes from the site
An Introduction to Formal Logic Introductory formal logic A corrected version of the second edition, freely available; the site also links to answers to exercises and supplementary materials
An Introduction to Gödel's Theorems Gödel's incompleteness theorems, full-length treatment Freely available, with related materials
Gödel Without (Too Many) Tears Gödel's theorems, much shorter version Freely available alongside the longer book
Introducing Category Theory Introductory/intermediate category theory Listed among the category theory resources, which also include lecture notes and other freely available books
Beginning Mathematical Logic: A Study Guide Orientation to studying mathematical logic Described as "much-downloaded"; includes an appendix reviewing wider-ranging books on mathematical logic

The site also refers to "The Five Big Red Logic Books" as open access, which is the headline framing for the textbook collection.

How to choose between them

  • New to logic entirely: start with An Introduction to Formal Logic, then use the linked exercise answers to check your work.
  • Want the shortest route into Gödel: read Gödel Without (Too Many) Tears first; go to An Introduction to Gödel's Theorems if you want the fuller treatment.
  • Deciding what to study more broadly: Beginning Mathematical Logic: A Study Guide is designed for exactly this — it maps the subject and its literature rather than teaching one topic.
  • Interested in category theory: use the category theory page, where Introducing Category Theory sits alongside lecture notes and other free books at introductory/intermediate level.

Beyond the textbooks

The site's Study Guide and Book Notes section pairs the study guide with an appendix and links to roughly forty further book notes — short reviews/notes on individual logic books. These are useful when you already have a reading list and want an assessment before committing time to a title.

There is also a LaTeX for Logicians section, pointing to resources for logicians, philosophers, and others who use LaTeX. If your work involves typesetting logic (proof trees, symbols, tableaux), this is the part of the site to check.

Practical notes

  • The site is organized into clear sections: Blog, IFL (the formal logic book), Gödel, Categories, Study Guide, Archive, and LaTeX for Logicians. Navigating by section is faster than searching.
  • The blog carries occasional posts on logic and related topics, and the Archive collects older posts, papers, and reviews — useful if you want commentary rather than textbooks.
  • The site was last updated September 29 (18:54), so the download links reflect a maintained collection rather than an abandoned one.

If your goal is simply to get a free, self-contained logic textbook today, An Introduction to Formal Logic is the direct starting point; if your goal is to plan a longer course of study, download Beginning Mathematical Logic: A Study Guide first and let it point you to the rest.