On the Origin of Species more recent study by science historian John van Wyhe has determined that the idea that Darwin delayed publication only dates back to the 1940s, and Darwin's contemporaries thought the time he took was reasonable. Darwin always finished one book before starting another. While he was researching, he told many people about his interest in transmutation without causing outrage. He firmly intended to publish, but it was not until September 1854 that he could work on it full-time. His 1846 estimate that writing his "big book" would take five years proved optimistic. An 1855 paper on the "introduction" of species, written
Genetics and the Origin of Species of Species" in 1859." Dobzhansky was plagued by a form of leukemia in his later years, but he remained vigorously active until the day before his death on December 18, 1975. During his lifetime he was the recipient of many honors and awards. For "Genetics and the Origin of Species" Dobzhansky was awarded the Daniel Giraud Elliot Medal from the National Academy of Sciences in 1941. Sixty years after its publication, the National Academy of Sciences commissioned a book entitled "Genetics and the Origin of Species: From Darwin to Molecular Biology 60 Years After Dobzhansky". It was also included in