The Testament by John Grisham 5

 

"You die with eleven billion, and people care about your last will and testament. Especially if there's a chance that one of the world's great fortunes is about to be fed to the vultures. The tabloids were there, along with the local papers and all the important financial magazines. The three rows Wycliff had designated for the press were full by nine-thirty. The journalists had a delightful time watching the Phelans gather in front of them. Three artists worked feverishly."

           -from the novel

Troy Phelan is one of the richest men in the world and, nearing death changes his will in a very sneaky way. He has 3 ex-wives and many adult children who can't wait to get their hands on some of his great wealth, and it seems none of them are very deserving.

Nate O'Reilly, a D.C. litigator just out of rehab and way down on his luck is tapped to find the actual recipient of the Phelan fortune. She is Rachel Lane, Troy's illegitimate daughter about whom little is known except that she a missionary in a remote area of Brazil. 

Nate is lucky to survive a plane crash and boat problems in his search for the woman. Fortunately, he has a river guide named Jevy, who, by the way, adds some humor to a story that gets pretty intense.

I found this to be a page-turner; the rating is 5.