Sahara by Clive Cussler (1992)
I have read many of Clive Cussler’s books, including most of those with Dirk Pitt as the hero. Recently I watched the movie Sahara and was very disappointed by the way the star portrayed Dirk Pitt. The movie did not do justice to the book and almost made the hero appear as a comical character.
For a complete synopsis of the book, check out the author’s website.