I read Tom Clancey's "The Hunt For Red October" when it was first published by the Naval Institute Press and was hooked. All of his original works are worth the read. Unfortunately he passed away and other authors have tried to continue his characters. These subsequent books are noticeably different in writing and content and IMO substandard.
Another prolific author who also recently passed away is (was) W.E.B. Griffin. He writes semi-historical fiction, intertwining fictional characters interacting with actual historical personages. It all started with "The Lieutenants" in his "Brotherhood of War" series. Here's his web site:
W.E.B. Griffin :: The Books
The stories have some racy elements (but not porn by any stretch). I've read them all except for the "Badge of Honor." Just not interested in cop stories. Although with his passing, I might. Buying them in hardback from discount bookstores has been my guilty pleasure. For me, reading for pleasure involves an actual book in my hands. Just can't adjust to reading on a tablet or other electronic device.
His last few books were co-authored with his son, William E. Butterworth IV. I'm waiting to see if the son continues with his father's stories and if so, are they up to the father's standards.