E. J. Lemmon (1930–1966)

Explains in a very clear way how to use propositional calculus in order to verify the validity of an argument. There are still some things I have difficulty with, and I might have to read some more stuff in order to be ready for my exam in logic on Feb 3rd.

Looks like a good introduction to the subject, but really dry and there's no way I'll manage to plough through it without actually doing some kind of course on logic!