Ernst Haeckel never really cared much for medicine. His practice was open only for an hour, from 5 to 6 a.m., so he could devote himself to his true passion, zoology.

Haeckel was inspired by Darwin's "Origin of the Species," which he said helped to shed light on the "dark chaos" of biological knowledge in the mid-1800s. Indeed, Haeckel was seen as instrumental in spreading Darwin's ideas across Europe, explaining evolutionary science in ways that laypeople and skeptical scientists could grasp.

Haeckel illustrations of cnidaria anthozoa from the book The Art and Science of Ernst Haeckel
(Photo: Taschen Köln)

Haeckel drew intricate renderings of the flora and fauna he encountered during his travels and expeditions. These illustrations range from jellyfish to organisms that Haeckel had only seen under a microscope. The drawings are so revered that they're still included in textbooks to this day.

Illustration of Anthomedusae by Ernst Haeckel
(Photo: Taschen Köln)

Luckily, you don't need a textbook to appreciate Haeckel's art now. "The Art and Science of Ernst Haeckel" is a sizable book that blends biography, science and art history to put Haeckel's illustrations into historical and contemporary context. The book also contains some of Haeckel's manuscripts, including "Kunstformen der Natur" ("Art Forms in Nature").

Ernst Haeckel illustrations: Disconalia gastroblasta
(Photo: Taschen Köln)

Haeckel's illustrations look like they should accompany Jules Verne's "Journey to the Center of the Earth" or be on the cover of a pulpy comic book about aliens. They are instead startlingly true-to-life, a reminder that there are plenty of fantastical creatures right here on our own world, even when we sometimes can't see them.

Ernest Haeckel: Protozoa illustrations
(Photo: Taschen Köln)

Take, for instance, Haeckel's illustrations of protozoa from "Kunstformen der Natur," pictured above. The illustration of these microscopic spiny organisms are all different species named by Haeckel.

Haeckel Illustrations: Jellyfish
(Photo: Taschen Köln)

Jellyfish account for many of Haeckel's illustrations. He named one species Desmonema annasethe (figures 1 and 2, above), after his wife, Anna Sethe. Many of the species he discovered were named for her. She died a mere 18 months into their marriage.

Haeckel even decorated the ceilings of his house in a jellyfish motif, and dubbed the residence the Villa Medusa.

Haeckel illustrations: Guancha gracilis and Soleneiscus japonicus
(Photo: Taschen Köln)

Haeckel's illustrations transcend scientific and public interest. As Julia Voss, a scientific historian and art critic writes in the collection, artists like Alfred Kubin and Gustav Klimt were influenced by Haeckel's work.

"We know of many artists active around 1900 who were familiar with Haeckel's books. Not only were they attracted chiefly by the sheer diversity of forms he had revealed, but also by the distinctive 'mood' conveyed by these animal and plant forms."

Haeckel Illustration: Thamnostylus dinema
(Photo: Taschen Köln)

Another jellyfish illustration, this one of Thamnostylus dinema, demonstrates Haeckel's value as a scientific illustrator, capturing an organism from many angles.

As Rainer Willmann, one of the editors of the collection, explained to the Guardian, "Instead of drawing just a front view, he also illustrated the other side if visible through gaps and holes in the skeletons. The result was a three-dimensional picture — rarely seen until then."

Willmann continued: "Many of Haeckel’s contemporaries thought that he went too far with his stylistic flair — but he knew all too well that a wide audience must be reached to get support for the natural sciences and the idea of evolution. To combine scientific accuracy with the presentation of natural beauty reflects his philosophy — that everything in the universe coheres."

Haeckel illustrations: True jellyfish in gold
(Photo: Taschen Köln)

And cohere it has.

As Willmann writes in the introduction to the collection, "On account of the sheer range of Haeckel's areas of research and interest, and the complexity of his trains of thought, it is hard to do full justice to him. In many fields his contributions had an influence that endures to this day. It is, above all, to Haeckel that we owe the fact that philosophy has begun to take into account the findings of biology and that contemporary studies in the humanities and the sciences have, in many respects, begun to interact with and to complement each other."