A textbook must provide, first and foremost, information to assist the reader in better understanding the topic. Second, it ought to provide the information in a way that can be easily accessed and digested, and it needs to be credible. Textbooks that have gone through multiple editions continue to improve as a result of reviewers' comments and readers' feedback, and this one is no exception. Looking back over the efforts associated with this Fifth Edition, the old wedding custom of "something old, something new, something borrowed, something blue" comes to mind. We have built upon the solid foundation of previous editions, but then added "something new." It almost goes without saying that we have "borrowed" from others in that we both cite and quote examples of program evaluation studies from the literature. "Something blue" . . . well, we're not sure about that.