I've read a lot of true-crime/forensic-science books, and this one's the first I've encountered in this format: grouped by concepts such as "crime scene processing," "trace evidence," "cold cases" etc., it consists of snippets from a number of different experts, from very short paragraphs to multiple-page entries, but with most of the contributions less than a page long. Described by the author as an oral history of personal experience, anecdotes about specific cases, commentary on how technology has changed, and so forth.