The Michael Bennett series is my favorite. LOTS of Catholic flavor but very “gritty”. I was shocked when I went back to my old high school for Career Day (they asked me to speak as an alumnus who happened to be a published author, though I would never recommend writing fiction as a career choice) and my old principal, who is an elderly nun in a black habit, confessed to being a HUGE fan of the Alex Cross series. I nearly choked on my coffee!