Amid the barrage of Ukraine horrors, many of us stole a microsecond this month to welcome the return to Cambridge University of two missing notebooks that once belonged to Charles Darwin.

The notebooks, from 1837-38, capture Darwin’s first major steps on the intellectual road that eventually led to his theory of evolution. The two tiny books had been reported missing in 2002 from Cambridge’s library. Returned anonymously, they arrived in a pink gift bag containing an archive box; inside that was a plain brown envelope. Accompanying the notebooks was a note that read: “Librarian / Happy Easter / X”

The notebooks’ contents were photographed and transcribed long ago and have been exhaustively studied for decades. So the originals’ value to scholars is strictly iconic. Even so, the hoopla that greeted their return highlights the ongoing public interest in a scientist who died a century and a half ago. And that raises a question: Why does Darwin still compel us so viscerally?

Certainly, the unexpected return of missing papers associated with, say, Galileo, Isaac Newton, or Albert Einstein would generate headlines. But unlike Darwin’s, those guys’ works seem settled business. When, after all, was the last time a pope tried to compel obeisance to Ptolemaic astronomy? Or for that matter, has anyone in recent memory questioned that Newton’s laws of motion or Einstein’s theory of relativity is taught in public schools?

But Darwin still stirs controversy, as much as anything because he remains misunderstood. School boards still debate whether to teach him, conspiracy theorists still weave him into conspiracies, and theologians still argue over the compatibility of evolution with religion. Indeed, his work has been used — and often distorted — by social and political activists on the right and the left ever since “On The Origin of Species” was published in 1859.

Many of the controversial ideas attributed to Darwin actually descend from the British biologist and philosopher Herbert Spencer. A generation younger than Darwin, Spencer founded what by the late 1870s was known as social Darwinism. “Survival of the fittest” was Spencer’s coinage; he used Darwin’s ideas to justify British colonialism and imperialism. For the most part, however, Darwin remained aloof from — even bemused by — Spencer’s thoughts. “With the exception of special points,” Darwin wrote in 1874, “I did not ever understand H. Spencer’s general doctrine; for his style is too hard work for me.”