Thure Kumlien was one of Wisconsin’s earliest Swedish settlers and an accomplished ornithologist, botanist, and naturalist in the mid-1800s, though his name is not well known today. He settled on the shore of Lake Koshkonong in 1843 and soon began sending bird specimens to museums and collectors in Europe and the eastern United States, including the Smithsonian. Later, he prepared natural history exhibits for the newly established University of Wisconsin and became the first curator and third employee of the new Milwaukee Public Museum. For all of his achievements, Kumlien never gained the widespread notoriety of Wisconsin naturalists John Muir, Increase Lapham, or Aldo Leopold. Kumlien did his work behind the scenes, content to spend his days in the marshes and swamps rather than in the public eye. He once wrote that he was not “cut out for pretensions and show in the world.” Yet, his detailed observations of Wisconsin’s natural world—including the impact of early agriculture on the environment—were hugely important to the fields of ornithology and botany. As this carefully researched and lovingly rendered biography proves, Thure Kumlien deserves to be remembered as one of Wisconsin’s most influential naturalists.