It is common knowledge that Rudolf Diesel (1858 - 1913) was a gifted engineer. However, it is almost unknown that he was also a significant visionary of social reform. In 1903, his book "Solidarismus" was published in an edition of 10,000 copies, of which only a few hundred were sold. Today, only 5 copies are preserved in libraries, and the book is completely absent from antiquarian shops. Unlike the scientific socialism of Marx/Engels, which aimed at the abolition of private property, expropriation, and socialization, Diesel sought to build capital and create new social conditions through new means. His model, based on voluntariness and the persuasive power of his economic calculations, aimed to achieve this without violence and coercion. Diesel hoped for support from the labor movement but was disappointed. The circumstances surrounding Diesel's death still generate intrigue today.