On Being Presbyterian is designed to introduce Presbyterianism to those who are new to it, or those who wonder what Presbyterianism is. It is written on a popular level for laymen. The book is divided into three sections: Beliefs, Practices, and History of Presbyterianism.

The focus of the book is on evangelical and reformed Presbyterian churches, particularly the PCA of which the author is a member. Sean Lucas is dean of faculty and assistant professor of church history at Covenant Theological Seminary, the PCA Seminary.

In the course of this short book, he touches on many important aspects of Presbyterianism and generally does a fine job of summarizing the Presbyterian position.