Logic: The Art of Defining and Reasoning (Prentice Hall, 1963) by John A. Oesterle is the introduction to Aristotelian logic (read: the system of logic that ruled the West for two millennia) for those who would rather not plow through Aristotle. Or, better, for those who would like a summary and workbook on hand as they grapple with the Philosopher himself.
The list price for this not-very-large book is astonishing to me – $60 for a cheaply bound facsimile of a book published in 1963 (and originally published more than a decade before that), but since the copyright was renewed in 1980, it’s not in the public domain, and Prentice Hall can charge whatever it wants. Used copies of the various editions are usually available, and sometimes, with searching, one can even run across a copy for less than $20. If you ever see one, grab it!