Trixie Belden And The Mystery On The Mississippi, writtn by Kathryn Kenny, illustrated by Harris Petie, cover by Paul Frame. Hardcover, 254 pages. A Golden Press book published by Western Publishing Company, copyright 1967, and published in the U.S.A.. 

Synopsis: Trixie Belden and the Mystery on the Mississippi by Kathryn Kenny is the fifteenth book in the Trixie Belden series. The story begins when Trixie and her friends, the Bob-Whites, are invited by Mr. Wheeler, Honey and Jim's dad, to travel with him as he takes a business trip down the Mississippi River. Upon arriving in St. Louis, Trixie discovers some mysterious papers in her hotel room trash can. She soon realizes that she and her friends are being followed by a man who is trying to steal these papers. Trixie becomes convinced that the man is a spy and the papers are linked to the top-secret space program. The mystery unfolds as Trixie and her friends embark on a thrilling adventure down the Mississippi River. They encounter various challenges and solve puzzles while trying to stay one step ahead of the mysterious man. Along the way, they decipher the coded messages on the graph papers and uncover the truth behind the stolen documents.

The book's spine, binding, and inner pages are all in very good condition. The front cover has a small number written on it in pencil, and the back cover has a few smudges.  There is black marker at the top of the page on the inside of the front cover (see photos).