Maupertuis was one of the most important scientists and original thinkers of the 18th century. He refuted the preformationist theories of the time, and from his study of the inheritance of genetic traits proposed various ideas which forecast the genetic theory of inheritance. He applied the concept of probability to genetic problems and introduced experimental breeding as a means of studying the inheritance of genetic traits in animals. However, he considered his greatest contribution to science to be the 'Principle of Least Action'. Yet paradoxically it was this, through the vitriolic attacks by Voltaire which it engendered, which resulted in his work being largely ignored until recent times.