If you're a typical Louis L'Amour fan, I already know a couple things about you.
First, you've read more of his books his books than you could possibly recount without some serious thought... and second, there was a first book you by read him that got ya hooked out of the gate.
For me the book was BRIONNE, first published in 1968; a Bantam paperback original with an attractive painted cover [Mine was, I think, the exact edition pictured above.]
Although it's never listed as one of Louis' best books, it was still a great introduction the man's work. The fast paced story concerns a westward trek made by a typical L'amour hero [Major James Brionne] and his son Mat, who are-- of course-- being pursued by some bad guys from Brionne's past. Along the way there are 2 mysterious strangers [one male, one female]; some great frontier wisdom imparted from father to son; and a pretty well-written prairie fire sequence.
When I say Brionne is a typical L'Amour hero, I mean that he is well-read, well-educated, an army veteran, and has a strong sense of his own ancestry [In this case the forebears are french, which was-- of course-- somewhat autobiographical for Louis himself.]
I agree with Harlan ellison that what really set Louis aside from all the other competition was his often under-rated writing style, which always conveyed a straight-froward sense of courage and wisdom. Brionne is just plain good company.
All in all, a great read even... when I peruse it today.