"Christopher Webber's book, Welcome to the Episcopal Church, is a very good, brief introduction to the Episcopal Church in history, worship and overall faith. Often used as a study guide or textbook during confirmation and new member classes, this book provides a clear, basic, accessible and interesting narrative that is easy to follow and easy to learn." - Fr Kurt Messick
Welcome to the Episcopal Church: An Introduction to Its History, Faith, and Worship is available from Amazon.com.
Another primer, geared toward confirmation classes, is Joseph B. Bernardin's Introduction to the Episcopal Church, also available from Amazon.com.