LANCER/ACE paperback editions 1966 - 1977 these are all so books co written by L. sprague de camp and lin carter with art by the great Frank Frazetta:
1) conan 1968
2) conan of cimmeria 1969
3) conan the freebooter 1968
4) conan the wanderer 1968
5) conan the adventurer 1966
6) conan the Buccaneer 1971
7) conan the warrior 1967
8) conan the usurper 1967
9) conan the conqurer aka the hour of the dragon 1967
10) conan the avenger aka the return of conan 1968
11) conan the aquilonia 1977
12) conan of the isles 1968
now these books I have read mostly because I loved the art so much. and this is where I came into conan for books.
I first came to Conan through the Lancer editions, as did most people. However, I would suggest that any readers now first coming to the series stick to Howard's originals, as they are readily availible in many trade paperback editions (as much of Howard's work is now in the public domain).
I read the first Lancer compilation under the impression that it was all Howard's work, and not knowing that it consisted mostly of pastiches by L. Sprague DeCamp and Lin Carter. There were seven or eight stories in that first volume. When I finished it, I said to myself, well two of the stories in that book were awesome, but the others were kinda lame. Guess this Howard fella wasn't all he's cracked up to be." Later on, of course, I learned that the two stories I liked were the only two original Howard stories in that first volume.