Isaac Newton (1642-1727)

Kneller Portrait of Newton (1689)

What Des-Cartes did was a good step. You have added much several ways, & especially in taking ye colours of thin plates into philosophical consideration. If I have seen further it is by standing on ye shoulders of Giants.

Newton to Robert Hooke (February 1675)

Internet History of Science Sourcebook
Mathematicians of the 17th & 18th centuries
Jesuits & the Sciences: 1540-1995 (Loyola University)
The Noble Dane: Images of Tycho Brahe (Oxford)
Johannes Kepler: The Laws of Planetary Motion
The Galileo Project (Rice University)

Short Biography, by Richard Westfall
Longer Biography, by Robert Hatch
Newton, A Short Account of the History of Mathematics (4th edition, 1908), W. W. Rouse Ball

Excerpts from the Principia
Excerpts from the Opticks
Newton's Rules of Reasoning
Quotations & Poetry
On the Shoulders of Giants
Voltaire: Letters on Newton (c. 1778)