Story/Novel Identification:

A human is paid/contracted to integrate with a desert people who are VERY in-touch with the desert - a la Avatar?

I remember the desert people were taller and thinner than humans, used Saracen-style Scimitar swords, had their own alien language, and over the course of the book (books?) integrated this man into their society.

He ultimately went native -- I remember this because he would wear their robes, bathe with sand, and shave all of his body hair.

It's a book I read in the early 90's, and I would like to read it again, but my Google-Fu has failed me. :(

I appreciate any pointers!