Another deceased author I was entranced by is Patrick O'Brian, whose Napoleonic War sea novels featuring Captain Jack Aubrey, is one I approached cautiously after seeing the film "Master and Commander" based more or less on his books.
As a lifelong fan of C.S. Forester and his hero Captain Horatio Hornblower, I was dubious that anyone else could approach his standards of authenticity. I was therefore amazed to discover that O'Brian leaves Forester in the dust. His books are far superior in every way, and I doubt that I will ever be able to read a Forester book again without making unfavorable comparisons.
There are 22 books to this series and the stories pretty much meld chronologically.
I second this, most emphatically.
Also of note is O'Brian's pair of books about Commodore Anson's earlier expedition to the Pacific to attack either the Manila or Acapulco Galleon, depending. Superb! Plus, he has written a few more outliers of various types and I look forward to reading them in time. His character development through dialogue is unmatched in my experience, as is his authentic details, e.g. his descriptions of the details of life at sea. His Aubrey/Maturin novels are available in a 4-volume set and they make a super gift for a reader.
Regards, Joe