To create a successful “gateway” apologetics book, you need, I think, three things, and all three of these are present in the case of Cold Case Christianity (CCC).
The first is a command of your material. Author J. Warner Wallace, a former atheist and cold case detective who now works for the Stand to Reason ministry, has that. Like most gateway books (like Lee Strobel’s), CCC offers a satisfying introduction to numerous critical issues in apologetics, such as the existence of Jesus, the reliability of the Gospels, and the Resurrection. Obviously, this means it does not cover the material in the same depth as something like my Shattering the Christ Myth or Licona’s The Resurrection of Jesus. It isn’t supposed to. This is something you hand to a new believer or an honestly inquiring non-believer, and it is a pleasure to see that Wallace has sifted the issues well, to the point that his bibliography includes some serious scholarly works.
Second, a gateway work needs a theme. In Lee Strobel’s case, that was the theme of an interviewing journalist. For Wallace, the theme is his past work as a cold case detective, which he uses as a framework to explain the issues and how to approach and think about them. I was naturally interested to see how this worked, given my background in corrections and that Mrs H and I enjoy the crime shows on the tube, including stuff like Cold Case Files. The answer is that it works very well, and that should be no surprise since in a way, it’s much the same approach as the “legal apologetics” theme used by authors like Simon Greenleaf. Detectives like Wallace are just at an earlier link in the chain.
Finally, a gateway work needs someone who can write coherently. Wallace certainly has this down; his prose is accessible and flows smoothly, and CCC is laid out in the same way as the popular Dummies guides, with little sidebars and illustrations to keep things interesting for the average reader. (Caveat: I happen to find such arrangements annoying, personally. But that’s my own preference – many more readers will appreciate it.)
CCC has earned a place in my bibliography of “gateway” apologetics books.