In a basement laboratory of the Morgan Library and Museum in New York, an X-ray scanner is pumping invisible beams into a clump of charred parchment leaves that looks as delicate as a long dead flower.

The leaves are the remains of a severely scorched early book, or codex, which was written in southern Egypt some time between 400 and 600 A.D. It contains the Acts of the Apostles, one of the books of the New Testament, possibly bound with another work. The writing is Coptic, the language of Egypt before the Arab conquest in 642 A.D.

The charred codex was purchased by the Morgan Library in 1962. But no one has opened it for fear of destroying it: The brittle pages have been fused together by a cinder that sank through much of the book, congealing the parchment fibers. Unlike famous codices that have their own names, like the Codex Sinaiticus, this one is known humbly as M.910, its accession number at the library.