To some, a misguided Lamarckian and a fraud, to others a martyr in the fight against Darwinism, the Viennese zoologist Paul Kammerer (1880-1926) remains one of the most controversial scientists of the early 20th century. Here his work is reconsidered in light of turn-of-the-century problems in evolutionary theory and experimental methodology, as seen from Kammerer's perspective in Vienna. Kammerer emerges not as an opponent of Darwinism, but as one would-be modernizer of the 19th-century theory, which had included a role for the inheritance of acquired characteristics. Kammerer attempted a synthesis of Darwinism with genetics and the chromosome theory, while retaining the modifying effects of the environment as the main source of favorable variation, and he developed his program of experimentation to support it. Kammerer never had a regular university position, but worked at a private experimental laboratory, with sidelines as a teacher and a popular writer and lecturer. On the lecture circuit he held forth on the significance of his science for understanding and furthering cultural evolution and he satisfied his passion for the arts and performance. In his dual career as researcher and popularizer, he did not always follow academic convention. In the contentious and rapidly changing fields of heredity and evolution, some of his stances and practices, as well as his outsider status and part-Jewish background, aroused suspicion and set the stage for the scandal that ended his career and prompted his suicide.