Despite recent leanings toward the left, I've enjoyed reading the Gabriel Allon series from Daniel Silva. Intelligent, well written with good characters and story lines. (in my opinion).

I've read all his books and have time to read others. I've read most of Barry Eisler (also like) and James Rollins (Sigma Force - started good but last half dozen+ have been lacking).

Tried Lee Child and not a fan of his writing style, a little immature and juvenile. I liked Clancy Rainbow Six but haven't ready anything else (anything good?).

Looking for recommendations for author / series, perhaps similar to Silva / Gabriel Allon in concept / theme.

If you are looking for a series and you liked Rainbow Six then the Tom Clancy Jack Ryan books are an easy recommendation. I suggest you read them in order starting with Hunt For Red October.

Clancy also wrote a standalone book Red Storm Rising that I thought was very good and re read several times. Would skip the Jack Ryan books written by other authors after Clancy died. They are not terrible but not at the same level IMO.

There is also the Vince Flynn Mitch Rapp series, Terminal list series by Jack Carr.

The Arliss Cutter series involving a deputy US Marshal based in Alaska by Marc Cameron is a slightly different genre but also a good.

I also did not really like the Lee Child Jack Reacher books, only read the first one, although others here do.

I don’t know how any of my comments refer to what you’re seeking, but possibly:

I agree about the Reacher series by Child; any thriller requires some degree of willing suspension of disbelief, but his required just too much. I was, however, reminded of the old Travis McGee series by John MacDonald, all of which I read long ago.

I liked the early Reece books by Jack Carr, but not so much the later ones that have almost drifted into science fiction. His latest, Cry Havoc, whose main character is the father of the previous books’ protagonist, has started to annoy me with the attitudes expressed about the Vietnam War. Perhaps something will change later in the book, but I’m not sure I’ll get to the point of finding out.

I really like everything Marc Cameron has written, including the Jericho Quinn series and his few Jack Ryan books.

I enjoyed most Bob Lee Swagger books by Stephen Hunter, but the unrelated The Bullet Garden was atrocious to the point that I really wonder if he actually wrote it himself.

For older historical fiction, I also very much liked the Aubrey–Maturin books by Patrick O’Brian. There were 20 (finished) books in the series and I’ve read the entire set three times; it’s almost time to start over.

Another old series are the Flashman books by George MacDonald Fraser. The “hero” of those books is a real reprobate, but I was totally hooked and much saddened when Fraser died. A great stand-alone book by Fraser was Mr American, and which cried out for the sequel that was never written.

Thanks guys. I know Clancy and may give that a shot although I've seen some of the movies (movies true to book?). I'll look up the others and sample them out. I'm open to trying new genres. That's what retirement is about, ain't it - trying new things you never had time to do before.

I read a lot of series, some are really good, some have seen better days.

David Baldacci has some fun series to read, he's prolific. His three Travis Devine books would be a good place to start.

Marc Cameron, really enjoy his.

Paul Doriron series featuring a Maine Game Warden are OK.

I'm OK with Jack Carr, Lee Child and Daniel Silva, not time wasted reading their books.