I enjoyed Athiest to Catholic, a short volume of conversion stories, which I received for review as part of the Tiber River reviewer program. Since each is written by a different author, some spoke to me more than others -- and that's no bad thing, since there should be at least one story that resonates with any person who picks it up. As a recent convert myself, I enjoyed reading about how others came to the Catholic faith, particularly from a background of atheism.
Atheist to Catholic - A Tiber River Review
Each story is self-contained, short, and easy to read. Having already made my decision to become Catholic, they were great reading; I'm not sure how much they would mean to someone still "on the fence." If that person, though, is just looking for a tiny little push, many of the reflections might serve.