This comprehensive introduction to symbolic logic covers informal logic and the syntax, semantics and metatheory of not only the classical propositional and predicate logics, but also for a number of extensions of classical logic and non-standard logics. It is the first textbook of this kind to provide substantive treatment of more recent developments in logic.
Covers sentential logic and predicate calculus in extreme depth. My only complaint is that it does not cover modal logic (Leibnizian or Kripkean) in anywhere close to the same detail. But, considering that it shows modal and other more advanced logics as a means of introducing logical pluralism, and not as a means of helping you necessarily learn these logics in depth, it is okay. Still would have loved even just a slightly longer passage on Leibnizian/Kripkean modal.
Fantastic introduction to Logic, provided you're blessed with access to an instructor. Syntax was understandable and while his explanation of meta-logic seemed overly opaque, the author can hardly be blamed for the web of abstraction that is meta-logic.