Sir Isaac Newton was an English mathematician, physicist and astronomer. His mother wanted him to devote his life to managing the family farm, but Newton had other ambitions. He studied mathematics and invented the calculus. Today he is recognized as one of the world's most brilliant mathematicians of all time. In his most important work, 'Principia', he introduced his laws of gravitation. This book is considered to be the most important and influential work in the history of science. His other great achievement was the invention of integral and differential calculus. New did not like to be involved in controversies. He was reluctant to publish his manuscripts because many of his discoveries where not consistent with what other scientists believed. One of these controversies was with the German mathematician, Leibniz. Their disagreement was over which of the two men actually invented the calculus. It now seems that Newton was working on this area of math before Leibniz but did not publish his work until after Leibniz did. Today historians believe that both men created their systems independent of one another. Newton was a modest man and also generous to those who helped him with his work. A quote attributed to Newton is: 'If I have seen a little farther than others, it is because I have stood on the shoulders of giants.'