Book excerpt: Starting from two unpublished manuscripts, this book attempts to revive an extraordinary, albeit poorly known, season of scientific research of the late XVIII century, which, from the study of the peculiar properties of some singular fishes, leads, through the unpredictable path of science, to the discovery of the electric nature of nerve signal, and, moreover to the invention of the voltaic battery. Besides presenting a crucial transition phase in the natural philosophy of the Enlightenment, this book is written with the ambition of reviving the fascination of science and its history.