Gerhard Heilmann (later sometimes spelt "Heilman") (25 June 1859 – 26 March 1946) was a Danish artist and paleontologist who created artistic depictions of Archaeopteryx, Proavis and other early bird relatives apart from writing the 1926 book The Origin of Birds, a pioneering and influential account of bird evolution. Heilmann lacked a formal training in science although he studied medicine briefly before shifting to art. His ideas on bird evolution were first written in Danish in the Dansk Ornitologisk Tidsskrift. Heilmann received little help and often got considerable opposition from Danish professional zoologists of the time and he in turn often made dismissive remarks on the ideas of some of the established scientists of the time. The English edition however reached out to a much larger audience and influenced ideas in bird evolution for nearly half a century. Source: Wikipedia (en)