Gr 1-3 In 1972, when Marjorie Weinman Sharmat wrote Nate the Great , the mystery series that followed was among the first successful beginning reader chapter books that quickly became a favorite of young readers. Now 50 years and 29 books later, Sharmat's son Andrew is telling the stories of the pancake-loving boy detective and his dog Sludge. Their latest case involves finding the missing Mr. Butler, a small solar-powered robot programmed to vacuum up dirt off the floor, which is the project entry from Mr. Scholari's class for the Earth Day Fair. Wearing his trademark Sherlock Holmes deerstalker cap and trench coat, Nate follows the clues from room to room. As with other titles in the series, Nate narrates his every step, a plot mechanism that keeps young readers involved in the mystery as they follow the colorful illustrations shown on every page. Along the way, he encounters other Earth Day projects like "Hi-Tech Hex," the large robot guard cat; a giant dark cloud used to keep plants moist; a fake soil recipe that produces a bumper crop of colorful vegetables; and some giant, slimy earthworms that can help farmers grow more food. The big question is, will Nate find Mr. Butler in time for the Earth Day Fair? The Ivanovs' illustrations are drawn in the style of the series' original illustrator, Caldecott Award winner Marc Simont. By reading the story and following along with the illustrations, young readers will readily become part of the caper. Nate is cued as white. VERDICT A recommended purchase; this title can be enjoyed as a standalone, keeping young readers happily caught up in Nate the Great's and Sludge's latest adventure.Cheryl Blevens, Cunningham Memorial Lib., Indiana State Univ.