In the mid-1730s, Elizabeth Blackwell did something that no one like her had ever done. Over the course of two years, she became the first British woman to produce a fully illustrated herbal — a kind of encyclopedic botanical reference guide — for commercial sale. The book was meant to aid scientists and doctors in developing and administering treatments for diseases through the use of plant-based therapies. Humans have long relied on plants for medical help, but previous herbals often featured limited or confusing images. By contrast, Blackwell’s specimens were observed from life in London’s Chelsea Physic Garden and rendered in large, detailed, hand-colored engravings. From local St. John’s Wort to the “curious love-apple” (tomato), Blackwell’s herbal features 500 plants from across the globe. Beyond its astonishing scope, the book also had serious scientific value. It predated and perhaps informed early modern works like “Species Plantarum” (1753) by Carolus Linnaeus, who we know...