Deborah Baker was born in Charlottesville and grew up in Virginia, Puerto Rico and New England. She attended the University of Virginia and Cambridge University. Her first biography, written in college, was Making a Farm: The Life of Robert Bly, published by Beacon Press in 1982.
After working a number of years as a book editor and publisher, in 1990 she moved to Calcutta where she wrote In Extremis; The Life of Laura Riding. Published by Grove Press and Hamish Hamilton in the UK, it was shortlisted for the Pulitzer Prize in Biography in 1994. Her third book, A Blue Hand: The Beats in India was published by Penguin Press USA and Penguin India in 2008.
In 2008–2009 she was a Fellow at the Dorothy and Lewis C. Cullman Center for Writers and Scholars at The New York Public Library. There she researched and wrote The Convert: A Tale of Exile and Extremism, a narrative account of the life of an American convert to Islam, drawn on letters on deposit in the library’s manuscript division. The Convert, published by Graywolf and Penguin India, was a finalist for the 2011 National Book Award in Non-Fiction.
In August 2018, she published her fifth work of non-fiction, The Last Englishmen: Love, War and the End of Empire.
She has two children and is married to the writer Amitav Ghosh. They divide their time between Brooklyn and Goa.