This poster tells the story of the One Book Ten Word Test. Assessment of knowledge and conceptual development is not easy. Multiple choice tests often produce results that are fragmented and sometimes trivial; with essays, it can be hard to distinquish good (or bad) writing from good (or bad) knowledge, and they can be time-consuming to score. The Ten Word Test is almost as efficient as a multiple choice test and produces valid and reliable evidence of deep knowledge. For 2009-10, Sacramento State's Community Engagement Center implemented a One Book program and selected When the Emperor was Divine, a short novel about the experiences of Japanese-Americans during WWII. The Center also developed a Ten Word Test to assess the ways in which participation in the One Book program promoted deeper understandings of the book's core concepts. Attendees are invited to score sample Ten Word items and talk about what we learned from its use.