Two notebooks that Charles Darwin filled with his ideas and his famous “Tree of Life” sketch have gone missing and are believed to have been stolen, the Cambridge University Library announced earlier today.

“On the Origin of Species” is doubtlessly one of the most influential books in history. It was heavily rooted in Darwin’s experiences and observations performed during the voyage of the HMS Beagle, completed in 1837 — which he recorded in leather-bound notebooks. One of them also held a diagram showing the possible evolutionary lineages of a certain species, which was later refined over the decades into the modern concept of a phylogenetic tree.

While not materially valuable, the missing notebooks are worth millions of pounds due to their connection to Darwin.

Long in the making

The library first lost track of the notebooks in 2001, after they were taken out of the Special Collections Strong Rooms to clear room for a photography project to be carried out there. They were listed as missing and it was assumed that someone filed them incorrectly somewhere in the collection, to be found eventually.

It takes quite a while to look through a library with over 10 million books, maps, and manuscripts, so the search continued and nobody was too worried. But a major search this year, the largest and most comprehensive effort of its kind ever undertaken at the Cambridge University Library, failed to produce the notebooks.

“Curators have concluded the notebooks […] have likely been stolen,” the library said in a statement.

Local police have been informed, they added, and the Interpol has updated their database of stolen works (“Psyche”) to include the notebooks. Jessica Gardner, the University Librarian, has also asked the public for help.

“I would ask anyone who thinks they know of the notebooks’ whereabouts to get in touch. Please help,” she said. “It is deeply regretful to me that these notebooks remain missing despite numerous wide-scale searches over the last 20 years”.

A project to significantly improve the library’s security systems has already been completed, and it will hopefully prevent the loss of any further materials. The appeal was made today, on November 24, as it marks the date of the first publication of “On the Origin of Species”. Anyone who may have information about the missing notebooks is asked to contact Cambridge University library via email at manuscriptappeal@lib.cam.ac.uk.