Two valuable Darwin notebooks missing for more than 20 years from the University of Cambridge in Britain and believed to have been stolen have been mysteriously returned to the university library in a gift bag containing a greeting card.

The two notebooks, one of which contains the sketch of the “Tree of Life” which became the symbol of the English naturalist’s evolution theory, “were delivered in good condition to the Cambridge University Library more than two decades after their disappearance had been was discovered”, the library states in its announcement.

The notebooks were delivered anonymously on March 9, 2022 in a pink gift bag with an envelope addressed to the librarian with “Happy Easter” on it, the announcement said.

“My sense of relief at the notebooks safe return is profound and almost impossible to adequately express,” said Jessica Gardner, director of library services.

“Along with so many others all across the world, I was heartbroken to learn of their loss and my  joy at their return is immense,” she added.

Gardner had launched a world wide appeal in November 2020 for the Darwin notebooks to saying they had “probably been stolen”. Their value is estimated at several million pounds. The local police had been notified and the notebooks had been added to the Interpol database for stolen works of art.

The two notebooks had been taken out of the strong room where the library’s most valuable works are kept to be photographed in September 2000. A routine inspection in January 2001 revealed that the small pocket-sized box containing them was no longer in their place.

For several years, the librarians believed that the notebooks had been misplaced in the library, which numbers approximately 10 million books, maps, manuscripts, and other items, and it was only in 2020 they concluded that they had probably been stolen rather than misplaced.

The works of Darwin (1809-1882), the father of the theory of evolution, made it possible for us to understand that the human being is neither at the center nor at the top of living beings.

The two rediscovered notebooks will be put on display this summer as part of an exhibition in Cambridge on to the scientist.