Bapu: Conversations and Correspondence with Mahatma Gandhi is an autobiographical description of F. Mary Barr's relationship and interactions with Mahatma Gandhi, whom she refers to as Bapu (father). Several of Gandhi's letters to the author, originally an English missionary in India, are included in full. The book was originally published in India in 1949. A revised edition was published in India in 1956. The book has been reviewed in several magazines, and discussed in other books.

In her Prologue, Barr describes the book as an "offering to thousands of persons all over the world who look up to... Gandhi, but have not had the author's opportunity of seeing him at work over a period of years". She explains that her intent is "to show Gandhi, the human being, to those many Europeans who are frankly puzzled by his personality, and... to give a great deal of detail such as would satisfy those who love him" and wish to learn even more about him. For the latter group, Gandhi's letters are "given with his exact wording, punctuation and headings". When Gandhi was asked if he would mind her writing a book, he said "Yes, you may write your book. It will remove come cobwebs".

A note from the publisher stated that the manuscript of the book had been received before Gandhi was assassinated, and that "it was felt that much of the feeling of devotion and understanding would have been lost if the present tense was changed, and so we prefer to present the book as if about a Living Personage".

Bapu opens with Barr explaining how she came to meet Mahatma Gandhi after having been in India for ten years in charge of a missionary boarding school in Hyderabad State. When she was in England on a furlough in 1931 she began to take an interest in Gandhi's writings and speeches. When returning to India, Barr had the good fortune of being a fellow passenger of Gandhi's on a ship from Italy to India, allowing her to become acquainted with Gandhi and observe the daily patterns of behavior of him and his small party of companions returning from the second Round Table Conference in London.

Later chapters describe Barr's correspondence and various meetings with Gandhi, how she was pressured by the British government and missionary authorities to end her association with Gandhi. her eventual resignation from her position at the mission, her visits to Gandhi at his ashram and in prison, how she spent time living at Gandhi's ashram, and how she eventually left the ashram in the service of Gandhi's movement. In an epilogue she states "The human personality depicted in the foregoing pages is no longer in the World as we knew him, but 'his soul goes marching on.' He brought religion into the service of the humdrum of daily life.... by sheer love and self-discipline he made mundane things beautiful: from pans to politics, he made them shine."

The book also contains a glossary of the meanings of about two dozen Indian words. Both editions contain an introduction by K. G. Mashruwala. The second edition contains an additional chapter, a tribute to Khan Abdul Ghaffar Khan, a comrade of Gandhi's, whose houseguest she was in 1941.

Reviews of Bapu have appeared in The Times of India, the Modern Review, the Indian Review and The Aryan Path

The Times of India viewed the first edition as having "succeeded very well", stating that the book was