Yep. That’s human skin alright.

In April, we published a piece about a book from Harvard University’s library that was bound not with regular leather, but human skin. Unfortunately, science ruined the party, confirming the next day that the book was actually bound in boring old sheepskin.

Thankfully, finally, mercifully, once again, fans of anthropodermic bibliopegy–or anthropodermic bliblioheads—have something to celebrate. Another book in Harvard’s apparently very spooky library, Des destinées de l’ame, or On the Destiny of the Soul by Arsène Houssaye, has been tested and confirmed to have been bound in human flesh, specifically that of a female mental patient who died of a stroke.

Back when the excitement about the other book—Practicarum quaestionum circa leges regias Hispaniae by Juan Gutiérrez—was boiling over, Daniel Kirby, a conservation scientist at Harvard University Art Museums’ Stratus Center used a technique called peptide mass fingerprinting (PMF) to turn off the stove. The results of the test ultimately proved that a mixture of cattle and pig collagen was used to bind Gutiérrez’s book.

However, they ran the same test of Houssaye’s book, and nobody can turn the stove off now. Bill Lane, the director of the Harvard Mass Spectrometry and Proteomics Resource Laboratory, in conjunction with Kirby, told the Houghton Library Blog the following:

“The PMF from Des destinées de l’ame matched the human reference, and clearly eliminated other common parchment sources, such as sheep, cattle and goat. However, although the PMF was consistent with human, other closely related primates, such as the great apes and gibbons, could not be eliminated because of the lack of necessary references.”

In an effort to fill in the blind spots, and forever give anthropodermites the hope and validation they’ve dreamed of, the scientists ran further tests to eliminate doubt left by the PMF. They used a Liquid Chromatography-Tandem Mass Spectrometry in order to analyze the amino acids, which are the building blocks of each type of peptide, and can differ in each species, as if nature constructed them specifically to give us this gift. The results were exactly as we all hoped they would be:

“The analytical data, taken together with the provenance of Des destinées de l’ame, make it very unlikely that the source could be other than human,” said Lane.

But, of course, we can’t just have people binding books in human skin for no reason. Even the most emphatic anthropodermic bibliopegs likely require a literary justification for such extreme measures. Again, like a gift from above, Houssaye delivers. A manuscript note that came with the book when it was deposited in the Houghton Library in 1934 informs readers that “a book about the human soul deserved to have a human covering.”

If that sounds a little bit like the type of thing a murderer might say on Criminal Minds, you’re not really that far off—though you are 500 or so years off. According to a Houghton Library Blog from 2013, the practice was somewhat common in the 16th century, when the confessions of criminals were occasionally bound in the skin of the convicted.

Do not worry, budding anthropodermian; this practice is not used only for evil. Individuals also used to be able to request that they be memorialized in the form of the book. So if you or your loved ones have a passion for anthropodermic bibliopegy, or you just happen want to leave them something really nice when you’re gone, the option is still on the table.