Comma placement question

[Brian0]

question on comma placement. Here's the sentence with which I'm working: "This is interesting because, as was noted in Fr. Gilsdorf’s previous book The Signs of the Times, ..." My question is, does a comma go after "book" or no? I can see it going both ways. Thanks.

[Powderhorn]

If Fr. Gilsdorf has only written one previous book, the comma is necessary because it species the one. If Fr. Gilsdorf has more than one previous tome, no comma. In either case, AP style dictates quotes around the title, and "Fr." seems questionable.