Growing up in the early 20th century, Fred Urquhart was fascinated by monarch butterflies and wondered where they went in winter. As an adult, he became an entomologist focused on tracking monarchs. But he didn’t do it alone. Norah, his wife, helped him develop a tag for the butterflies and publicize his work. Publicity was important, as they had embarked on the first monarch citizen science project, which relied on people (including schoolchildren) in the United States and Canada to help capture, tag, and release monarchs, and to report the tags of butterflies they found. Fred and Norah mapped and followed the data, driving south in search of the monarchs. They were home in Toronto in 1975 when two of their assistants in Mexico were guided by knowledgeable locals to the winter home of the monarchs; a year later, Fred and Norah saw it for themselves. Lively mixed-media illustrations are a bright accompaniment to this engaging account (although the book would have benefitted from in-text references to dates). The welcome, informative author’s note begins by acknowledging that people living in central Mexico were well aware of the monarchs wintering there long before researchers made this “discovery.” The volume concludes with a message from Dr. Karen S. Oberhauser, monarch researcher and director of the UW–Madison Arboretum.   (Ages 6-9)