Joseph Tyson has made several helpful suggestions concerning how to identify themes in a book. In general, he notes that, "In my view, the determination of dominant themes involves the utilization of literary-critical approaches that make few assumptions about the text" (106). He goes on to identify two important, but not essential, preliminary matters: genre and intended audience (106-7). Tyson argues that themes can be identified by "examining the clearly redactional sections," "repeated literary patterns," and "exemplary episodes that convey points of stress to which the author returns on several occasions," (107-8),
Tyson, Joseph B. “Themes at the Crossroads: Acts 15 in Its Lukan Setting.” Forum 4 (2001): 125–44.