Collection of important essays. Ernst Heinrich Philipp August Haeckel (1834-1919), also written von Haeckel, was an eminent German biologist, naturalist, philosopher, physician, professor and artist who discovered, described and named thousands of new species, mapped a genealogical tree relating all life forms, and coined many terms in biology, including phylum, phylogeny, ecology and the kingdom Protista. Haeckel promoted and popularised Charles Darwin's work in Germany and developed the controversial recapitulation theory. Sir John Arthur Thomson (1861-1933) was a Scottish naturalist who authored several notable books and was an expert on soft corals. He taught at University of Aberdeen from 1899 until 1930, the year he was knighted. His popular works sought to reconcile science and religion. Thomson's Outline of Science, published in 1922, sold more than one hundred thousand copies in five years. Friedrich Leopold August Weismann (1834-1914) was a German biologist. He was ranked the second most notable evolutionary theorist of the 19th century, after Charles Darwin. He graduated as a medical doctor and settled in Frankfurt. During the war between Austria, France and Italy in 1859, he became Chief Medical Officer in the military.