An extensive collection of Charles Darwin's private manuscripts is now available online. Previously, this collection of handwritten notes—penned by the naturalist who forever changed the way we would interpret the natural world—was only available to scholars at Cambridge University Library. Now Darwin's extensive writing can be viewed freely by the public.

The writings that are available online include the first draft of Darwin's theory of natural selection and the original notes from the voyage of the Beagle. The collection consists of over 20,000 items and 90,000 images.

In the 1940s, the Darwin family and the Pilgrim Trust (a charitable trust based in London) presented the manuscripts to the Cambridge University Library for preservation and study. In the decades that followed the manuscripts were organized into volumes and carefully preserved. In the 1990s, the writings were copied to microfilms. These images were later scanned and digitally enhanced to optimize contrast for online viewing. The images you can view online are not full-color reproductions of the originals.

Find out more:

• The Complete Works of Charles Darwin Online
• Browse Darwin's Papers
• The Zoology of the Voyage of H.M.S. Beagle
• On the Origin of Species
• The Descent of Man

Image: Portrait of Charles Darwin, painted by George Richmond.