This book shows how the thriller (using that term loosely) became more popular than "mainstream fiction" and "literary fiction" and, in the hands of some writers became as sophisticated.
Anderson's short list of "modern masters" includes Thomas Harris, George Pelecanos, Michael Connelly, Dennis Lehane and a few others, but he discusses many writers in several categories. I've added some new names to my to-be-read list. I also enjoyed his discussions of writers I've read such as Lawrence Sanders. It's nice to be reminded what is good about those books.
Throughout the book I found answers to questions I have long pondered. For instance, he says Sue Grafton's first book is about 200 pages, but a book from later in her Kinsey Milhone series runs to 337 pages. Anderson says this is not because the plot has more twists and turns, but rather because Grafton includes more description.
For me this was similar to another book about books I like, Books to Die For. The Triumph of the Thriller was published in 2007, so it ends before the rise of ebooks and print-on-demand, which uprooted many of the assumptions of book publishing.