Lord Tyger by Farmer is weird, weird book. A sort of deconstruction of Tarzan, of how you could actually get something in real life close to ERB’s vision. Not for the squeamish, if I recall he has his character having sex with the gorillas.
https://en.wikipedia.org/wiki/Lord_Tyger
Freegards
Did you ever read Lord of the Trees by Farmer? It was a companion piece to The Mad Goblin, but the latter featured a version of Doc Savage. The two books told the same story from different points of view; I first found them together as an Ace Double. Fun stuff.
That sounds about right, for Farmer. Back when I used to read scifi (so long ago, I recall shopping for one of his in a tidy little bookstore in the Ledyard Building, downtown Grand Rapids, been gone so long, I think the area was still French speaking at the time). I think I wound up getting one of the World of Tiers novels, or maybe there is only one? And in the mid-1980s I read "Venus on the Half-Shell", which he wrote under the ps-nym Kilgore Trout.