In ancient Egypt, death wasn't merciful enough to end one's troubles. The afterlife was fraught with peril, too, and the dead had to contend with something of a spiritual obstacle course to reach Rostau, the glorious realm of Osiris, god of death.

At least two paths to Rostau existed: one by land, another by sea. Both were arduous enough to require a guidebook, the aptly named Book of Two Ways. This intricate map of the ancient Egyptian underworld may be the first illustrated "book" in history. And archaeologists have now unearthed a 4,000-year-old-copy—possibly the oldest version ever found, reports Franz Lidz for the New York Times.

The find, described in a recent paper in the Journal of Egyptian Archaeology, nudges the history of ancient literature backward in time, underscoring the dedication and sophistication with which these individuals tackled the enigma of their own mortality.

"The ancient Egyptians were obsessed with life in all its forms," says Rita Lucarelli, an Egyptology curator at the University of California, Berkeley, in an interview with Lidz. "Death for them was a new life."

The newest (technically, oldest) copy of Book of Two Ways joins just two dozen others known to modern archaeologists. It unseats the previous record-holder by about 40 years, Colin Barras reported for New Scientist in October. Discovered in 2012 during excavation of a burial shaft in the Egyptian village of Dayr al-Barshā (or Deir El Bersha), the text was found in a coffin that had largely escaped the attention of both grave robbers and previous generations of archaeologists.

Unlike the bound books of modern times, the ancient text wasn't a standalone volume. Instead, excerpts were written on the inside of the sarcophagus itself, surviving in the form of two rotting cedar panels etched with images and hieroglyphs. The inscriptions clearly quote the Book of Two Ways, and other artifacts in the grave have been dated to the reign of Pharaoh Mentuhotep II, who ruled until 2010 B.C.

Easily accessible to the entombed, such "coffin texts" were meant to "situate the deceased in the world of the gods," study author Harco Willems, an Egyptologist at the University of Leuven in Belgium, tells Lidz. This particular sarcophagus was occupied by a high-status woman named Ankh, though the afterworld instructions in her final resting place actually refer to her as "he."

"The funny thing is the whole idea of how you survive in the netherworld is expressed in male terms," Willems told Barras.

In ancient Egypt, rebirth was linked most closely to male gods; dead women, then, had to adopt the pronoun "he" to be more like Osiris himself, Kara Cooney, an expert on Egyptian art and architecture at the University of California, Los Angeles, explains to Lidz.

But Ankh's Book of Two Ways still showed some hints of personalization. Her journey, the text portended, might have been waylaid early on by a ring of fire. Later, she may have dealt with demons, spirits and even earthly plights like fire. The only protection against these ills were spells cast by the deceased Ankh herself. Luckily, the companion text came with specific instructions on these incantations.

The "maps" of this book and others are muddled with meandering lines and ominous figures—symbols difficult to interpret in modern times. Some researchers think the depictions may have been drawn from images in life, rather than death, evoking rituals meant to bring deceased gods or humans back from the dead. Either way, the texts signified rebirth, in this world or another.

That makes excerpts from Book of Two Ways common fixtures of Egyptian graves. Already, this "oldest" copy may have a contender, Barras reports: a leather scroll version discovered by Egyptologist Wael Sherbiny, who has yet to publish his findings. Whatever is revealed next, archaeologists will certainly be vying for a glimpse—there's no two ways about it.