"An utterly fascinating guide to who you are and how you work. Saira Hameed reveals the endocrine system, and places it at the center of self-knowledge; a system of control, but also a set of signals we can learn to interpret. It's compassionate, humane and grounded in the author's deep clinical experience. A true gift." -Chris van Tulleken, author of Ultra-Processed People

"A fascinating tour of endocrinology, surely the most outlandish but also humane of the medical specialties. Hameed isn't just an exceptional doctor, she is a natural storyteller. Unputdownable!" -Gabriel Weston, author of Alive and Direct Red

"This is the book I have been waiting for since I was a teenager. Hameed's timely, brilliant, and engaging journey through the hormones that control our brains and bodies is infused not just with deep curiosity but with wisdom and compassion. Signals will make you question everything you thought you knew about the choices we make and the emotions we feel-men and women, and at every stage of our lives." -Aarathi Prasad, author of Silk and In the Bonesetter's Waiting Room

"A fascinating insight into the real-world mystery-solving of the doctors' clinic, and discoveries past and present." -Mishal Husain

"...the author is as eloquent as she is knowledgeable, and brings once ghostly "spirits" to vibrant life. A must-read in any era, but especially this one, given the increasing prevalence of hormone-centric drugs." -Kirkus

"Through patient case studies and the thrilling stories of the scientists behind the discoveries, Saira Hameed takes us on a journey through the hidden chemical conductors of our health. Hameed is the kind of doctor you'd love to be referred to: knowledgeable, compassionate and with knack for translating science into stories that inspire and entertain." -Caroline Williams, author of Inner Sense

"In this enlightening exploration, endocrinologist Hameed draws from decades of expertise and real-life patient cases to demystify the role of hormones in the body. Throughout, she combines entertaining storytelling with insightful reflections. Readers will be inspired to listen to their bodies' cues." -Publishers Weekly

"[An] enthralling, revelatory book." -The Bookseller (an Editor's Choice)