Historians, biographers, and scholars of John James Audubon and natural history have long been mystified by Audubon’s 1843 Missouri River expedition, for his journals of the trip were thought to have been destroyed by his granddaughter Maria Rebecca Audubon. Daniel Patterson is the first scholar to locate and assemble three important fragments of the 1843 Missouri River journals, and here he offers a stunning transcription and critical edition of Audubon’s last journey through the American West. Patterson’s new edition of the journals—unknown to Audubon scholars and fans—offers a significantly different understanding of the very core of Audubon’s life and work. Readers will be introduced to a more authentic Audubon, one who was concerned about the disappearance of America’s wild animal species and yet also loved to hunt and display his prowess in the wilderness. This edition reveals that Audubon’s famous late conversion to conservationism on this expedition was, in fact, a literary fiction. Maria Rebecca Audubon created this myth when she rewrote her grandfather’s journals for publication to make him into a visionary conservationist. In reality the journals detail almost gratuitous hunting predations throughout the course of Audubon’s last expedition. The Missouri River Journals of John James Audubon is the definitive presentation of America’s most famous naturalist on his last expedition and assesses Audubon’s actual environmental ethic amid his conflicted relationship with the natural world he so admired and depicted in his iconic works.