The right of Dava Sobel to be identified as the author of this work has been asserted by her in accordance with the Copyright, Designs and Patents Act 1988

A catalogue record for this book is available from the British Library

Cover images © Harvard University Archives, UAV 630.271 (D3091) (olvwork432332) / Harvard College Observatory (Harvard Women Computers, c. 1925)

Frontispiece image courtesy of Harvard University Archives

Insert page 1, bottom: Angelo Secchi, Le soleil, 1875–1877; page 2, top: Courtesy of Carbon County Museum, Rawlins, Wyoming; page 3, bottom: UAV 630.271 (E4116), Harvard University Archives; page 4, top: Courtesy of Harvard College Observatory; page 5, top: Schlesinger Library, Radcliffe Institute, Harvard University; page 5, bottom: Courtesy of Hastings Historical Society, New York; page 6, top: Courtesy of Harvard College Observatory; page 6, bottom: Lindsay Smith, used with permission; page 7, top: HUGFP 125.82p, Box 2, Harvard University Archives; page 7, bottom: Special Collections Research Center, University of Chicago Library; page 8, top: HUPSF Observatory (14), olvwork360662, Harvard University Archives; pages 8–9, bottom: UAV 630.271 (391), olvwork432043, Harvard University Archives; page 9, top: Courtesy of Harvard College Observatory; page 10, top: HUGFP 125.82p, Box 2, Harvard University Archives; page 10, bottom: Courtesy of Harvard College Observatory; page 11, top: HUGFP 125.36 F, Box 1, Harvard University Archives; page 11, bottom: HUGFP 125.36 F, Box 1, Harvard University Archives; page 12, bottom left and right: Courtesy of Katherine Haramundanis; page 13, top: Courtesy of the Harvard University Archives; page 13, bottom: Courtesy of Charles Reynes; page 14: Chart 1, Volume 105, Harvard College Observatory Annals; page 15, top: Courtesy of Hastings Historical Society, New York; page 15, bottom: Courtesy of Katherine Haramundanis; page 16, top: Lia Halloran, used with permission; page 16, bottom: Richard E. Schmidt, used with permission

All rights reserved under International and Pan-American Copyright Conventions. By payment of the required fees, you have been granted the non-exclusive, non-transferable right to access and read the text of this e-book on-screen. No part of this text may be reproduced, transmitted, down-loaded, decompiled, reverse engineered, or stored in or introduced into any information storage and retrieval system, in any form or by any means, whether electronic or mechanical, now known or hereinafter invented, without the express written permission of HarperCollins

Source ISBN: 9780007548200

Ebook Edition © November 2017 ISBN: 9780007548194

Version: 2017-09-14

To the ladies who sustain me:

Diane Ackerman, Jane Allen,

KC Cole, Mary Giaquinto, Sara James, Joanne Julian,

Zoë Klein, Celia Michaels, Lois Morris,

Chiara Peacock, Sarah Pillow,

Rita Reiswig, Lydia Salant, Amanda Sobel,

Margaret Thompson, and Wendy Zomparelli,

with love and thanks

Cover