In the mood to contemplate your own mortality? Then Jodi Picoult has the book for you.

The best-selling author's latest offering, "The Book of Two Ways," follows Dawn Edelstein, a former Yale Egyptology student turned death doula. In Dawn's orbit there's a whole lot of death, starting with Win, the dying woman she's caring for, the memories of those Dawn lost and the very, very deceased (as in mummified in Middle Egypt 4,000 years ago).

In short, if you are looking for comic relief, you are out of luck. But readers don't pick up Picoult for the LOLs. Instead, they come for the heart-wrenching moral choices, the complicated family dynamics, the deep dive into ethical issues, and, lately, the nonlinear plots. Picoult's last book, "A Spark of Light," told the story backward; "The Book of Two Ways" presents two possible timelines and settings: Land/Egypt and Water/Boston. This is an homage to an ancient Egyptian coffin text also called "The Book of Two Ways," which contains one of the first known maps of the underworld. While the ancient Egyptians believed that one could get to the afterlife either by land or water, Picoult's book is not "choose your own adventure." Instead, timelines occur simultaneously (think "Sliding Doors" but without Gwyneth Paltrow's iconic hairdo).

When we're introduced to Dawn, she boards a plane that soon begins to "fall out of the sky." As it goes vertical, she contemplates that "Ancient Egyptians believed that to get to the afterlife, they had to be deemed innocent in the Judgement Hall. Their hearts were weighed against the feather of Ma'at, of truth." She's not sure her heart will pass the test. Her guilt stems from her thinking not of her steady quantum mechanics professor husband, Brian, but of Wyatt Armstrong, a British Egyptologist whom she hasn't seen in 15 years. In what could be her final moment, she's grasping for another man, for the Egypt she left behind and the dissertation she never finished.

That's when the path breaks into two.

Option one: Dawn is a brilliant graduate student at Yale, an expert in "The Book of Two Ways." All is going as planned, including taking part in a dig in Egypt with Wyatt, when news that her mother is dying puts everything on hold. Turns out, that hold is going to be a long one. Stateside, Dawn meets Brian and soon after, Dawn and Brian meet marriage and a baby. Dawn pivots from the long dead to the dying, becoming a death doula, a job she's devoted to, especially with new patient Win who is trying to answer what-might-have-beens before she passes. Win's journey inspires Dawn to question her own lost loves: Wyatt and Egypt.

Option two: When the airline offers up their mea culpa to survivors of the crash in the form of a plane ticket, Dawn asks not for a one-way home, but a ticket to Cairo, knowing Wyatt is in Egypt, still digging, now making a name for himself, and perhaps still thinking about her.

It sounds simple enough, but it's not. Picoult weaves us around, at times not clarifying which story line we're in. Some readers may find the ambiguity frustrating, others may enjoy trying to figure out Dawn's path.

While there's ambiguity in the story, there's none regarding Picoult's passion for Egyptology. After 26 novels she is a master researcher, but she's also usually a master of weaving in information without letting it slow the pacing. Not this time. She knows her stuff, but she's showing readers her 200 best vacation pictures instead of 20. As a result, the history can feel heavier than a sarcophagus.

That heaviness aside, "The Book of Two Ways" is a return for Picoult to the themes of her earliest books — motherhood, complicated romantic love — when she did not build tension in a courtroom or hospital. Picoult, at this point in her career could skillfully build tension in a broom closet, but the best part of this book is not the suspense; it's the look at the complexity of a woman as she enters middle age. When Win muses that, "women don't get to have midlife crises where they run off to find themselves," Dawn instinctively knows she's right. "Men leave their wives and children behind every day, and no one is shocked," she thinks. "It's as if that Y chromosome they hold entitles them to self-discovery, to reinvention." But Picoult allows her protagonist to have both, and that backward reflection and forward glance lift the narrative, reminding fans that Picoult always tells both sides of a story not with judgment, but with grace.

Karin Tanabe is the author of five books, including, most recently, "A Hundred Suns."

The Book of Two Ways

By Jodi Picoult

Ballantine. 417 pp. $28.99