I used to live not far from a small but lovely botanical garden, overlooking the waters of The Narrows in Brooklyn. My favorite section was lush with Buddleia shrubs, whose nectar is irresistible to the monarch butterfly. Here in the play of late summer light, a quiet spectacle would unfold daily. Monarchs, their black and orange wings beating with ceaseless energy, flew in helter-skelter patterns, en route to their southern wintering grounds in Mexico.
The simple yet magical beauty of this scene is one familiar to the historian William Leach, whose new book, “Butterfly People,’’ was inspired by a lifelong love of these winged creatures. Looking at the lives of several 19th-century American naturalists who chased, named, and collected butterflies from the Rockies to the White Mountains, Leach tells us that the pursuit of butterflies — monarchs, swallowtails, the wonderfully named Baltimore checkerspot, among others — was central to the study of the natural world, “not merely at the margins of inquiry, but at the very core of it.”