books.google.com - Logic is sometimes called the foundation of mathematics: the logician studies the kinds of reasoning used in the individual steps of a proof. Alonzo Church was a pioneer in the field of mathematical logic, whose contributions to number theory and the theories of algorithms and computability laid the...http://books.google.com/books/about/Introduction_to_Mathematical_Logic.html?id=JDLQOMKbdScC&utm_source=gb-gplus-shareIntroduction to Mathematical Logic