I must add one most extra ordinary author since no one has mentioned him.
L. Sprague de Camp
Not possible to pick a “best” novel (you have to read his pedigree), but an historical fiction fantasy sci fi novel for any aged reader is “Lest Darkness Fall”. A 1939 publication that is not in the least dated. Seriously. You’ll see why.
Great book!
Would make a great movie that wokeism would ruin!