Jacket proof — The Longitude of Sleep, first cloth edition

Printed flat and read left to right, exactly as it leaves the press: turn-in flap, back board, spine, front board, turn-in flap. Fold marks are live.

Proof 04 / Rev C
Stock: Colorplan 175gsm
Trim 622 × 240 mm

01 · turn-in, verso

About the author

Marguerite Aleyn was born in Sète and spent eleven years cataloguing tide tables for the Institut Hydrographique before publishing her first novel, The Salt Register, at forty-three. Her work has been translated into nineteen languages and shortlisted twice for the Verrier Prize.

She lives on the Île de Ré with two greyhounds and an unreliable barometer.

Jacket design · Ines Baradóttir
Author photograph · P. Renaudin
Set in Iowan Old Style
Printed in Ghent

02 · back board

“A novel that measures grief the way a cartographer measures coastline — patiently, and always coming up longer.”

Aleyn writes weather better than anyone alive. The storm in chapter nine lasts thirty pages and I would happily have stayed in it for three hundred.
— The Vessel Review
A quiet, exacting book about the hours we lose and the instruments we invent to find them again.
— Aldous Fenn, novelist
There is not a lazy sentence in it. Extraordinary.
— Le Courrier des Îles

9 781904 421186

Fiction
£18.99 · $26.00
Halcyon & Rook

03 · spine

The Longitude of Sleep Marguerite Aleyn

04 · front board

Halcyon & Rook · New Cloth Series

a novelThe Longitude of Sleep

Marguerite Aleyn

05 · turn-in, recto

Jacket copy

In the winter of 1911, a lighthouse keeper named Ivo Sarn stops sleeping. Not from grief, he insists, though his wife has been dead eleven weeks — but because the nights have begun arriving at the wrong hour.

What follows is a record kept in three columns: the official log, the private one, and the one he burns each morning before the relief boat comes. As the winter deepens, the three accounts stop agreeing.

Marguerite Aleyn's fifth novel is a study of duration itself — of how a single unlit room can hold more hours than a calendar. Precise, tidal and unexpectedly funny, The Longitude of Sleep confirms her as the finest chronicler of northern weather and southern regret writing today.

£18.99 UK · Jan 2026

ISBN 978-1-90442-118-6
Also available as audiobook

Production notes

Rev C · approved

Jacket production specification
Flat trim	622 × 240 mm + 3 mm bleed
Spine width	34 mm, calculated at 512 pp on 80gsm Munken Cream
Turn-in flaps	92 mm each, folded to inside board
Stock	Colorplan Mist 175gsm, uncoated
Finish	Soft-touch matt lamination; copper foil on title and rule
Inks	2/0 — Pantone 5605 C + 4685 C
Proofing	Wet proof on stock, viewed at D50