In 1804, while Lewis and Clark were still making their way up the Missouri River, Thomas Jefferson formulated a plan for a similarly ambitious exploration that would proceed from the Mississippi up the Red River "to the tops of the mountains" and then return by way of the Arkansas River. The man he selected to lead this venture was William Dunbar (1750--1810) of the Mississippi Territory. The Scottish-born Dunbar was a man of many abilities and professions -- surveyor, botanist, zoologist, astronomer, planter, architect, inventor. He perfected the cotton bale, learned how to put cottonseed oil to use, and he improved agricultural implements to increase production. In addition, he published many scientific articles in American Philosophical Society journals. In William Dunbar: Scientific Pioneer of the Old Southwest, Arthur DeRosier finally gives Dunbar's fascinatingly varied life and career the recognition they deserve.