Louis Lewin was a prominent scholar in the intellectual life of Berlin at the turn of the 19th century and into the first quarter of the 20th century, serving as a toxicologist and author of several widely circulated specialist books. His extensive work and forward-thinking ideas continue to shape the field of toxicology today. With the Academy Verlag Berlin making available for the first time Louis Lewin's travel diary from a trip to the USA and Canada, it not only provides an interesting cultural-historical insight into the "travel culture" of nearly a hundred years ago but also offers a charming portrait of this exceptionally knowledgeable and socially critical toxicologist. We are particularly pleased that the Royal Swedish Academy of Sciences, in collaboration with the Academy of Sciences of the GDR, is involved in this endeavor.