When Cam and Eric go on a field trip to the museum with their fifth grade class, Cam - with her photographic memory - makes an interesting discovery: dinosaur bones are missing from one of the exhibits. When no one believes them, they decide to catch the thieves themselves. As they stake out the library, a mysterious milk truck stops by. Cam knows something is wrong. The logo on the truck does not match the logo on the milk carton they drank from at lunch. The game is afoot! Will they find the missing dinosaur bones when they follow the truck to a neighborhood house, or just a truckload of sour milk? Award-winning author David A. Adler is a former New York City math teacher. In addition to writing the Cam Jansen series, he has authored more than 100 books for children, including science and math text books, as well as biographies of world-famous historical figures.