THE MÖBIUS BOOK, by Catherine Lacey

The first thing to know about “The Möbius Book,” by Catherine Lacey, is that it is actually two books. One is a novella with a hint of murder mystery. Start from the opposite side, flipping upside down — how will this work on a Kindle? — and you’ll find the other: a memoir of breakup and friendship during the pandemic, interspersed with musings on religion.

Where will bookstores put this loopy blue thing? Amazon, with unusual resourcefulness, has nested it for now under Self-Help/Relationships/Love & Loss (though I’d wager the author’s core audience avoids Amazon).

One has come to expect such formal experiments from Lacey, especially after her bravura “Biography of X”: not a biography of anyone real, but a footnoted, name-dropping, time-melting fourth novel that made many best lists in 2023.

There are plenty of names pelted into “The Möbius Book,” too — author friends like Heidi Julavits and Sarah Manguso, and many others — but one notably missing in the memoir part is that of Lacey’s ex, which gentle Googling reveals is yet another writer, Jesse Ball. Here he is referred to as The Reason: the literary-circle equivalent, maybe, of The Weeknd.

He is the “reason” why she has become a visitor to, rather than a resident of, the house they bought together, after receiving an email he sent from another room, composed on his phone, telling her he’d met another woman. (At least not a Post-it?) He is also, or so she believed, a pillar of masculine rationality. With tattoos.