Here are pdf files containing known errors in some of my books. I would appreciate it if you would let me know of any additional errors you find in these or any other of my books.
First-Order Modal Logic, Melvin Fitting and Richard L. Mendelsohn, Kluwer, 1998, paperback 1999.
First Order Logic and Automated Theorem Proving, Melvin Fitting, second edition, Springer, 1996.
Set Theory and the Continuum Problem, (revised edition), Raymond M. Smullyan and Melvin Fitting, Dover Publications, 2010.
Set Theory and the Continuum Problem, Raymond M. Smullyan and Melvin Fitting, Oxford University Press, 1996.
Types, Tableaus, and Goedel's God, Melvin Fitting, Kluwer, 2002.
Incompleteness in the Land of Sets, Melvin Fitting, College Publications, 2007.
Next are a few solutions to some problems in First-Order Logic and Automated Theorem Proving. Hopefully, there are no errata here.
And here are paper errors. Surely there are more.