Question: Kai Bird and Martin Sherwin wrote a book about the father of what?
Context: Julius Robert Oppenheimer (April 22, 1904 – February 18, 1967) was an American theoretical physicist and professor of physics at the University of California, Berkeley.  Oppenheimer was the wartime head of the Los Alamos Laboratory and is among those who are credited with being the "father of the atomic bomb" for their role in the Manhattan Project, the World War II undertaking that developed the first nuclear weapons used in the atomic bombings of Hiroshima and Nagasaki.  The first atomic bomb was detonated on July 16, 1945, in the Trinity test in New Mexico; Oppenheimer later remarked that it brought to mind words from the "Bhagavad Gita": "Now I am become Death, the destroyer of worlds." Charles Dixon (1858-17 June 1926) was an English ornithologist, born in London.  He discovered the St Kilda wren and a new species in North Africa.  He collaborated with Henry Seebohm on his great work on "British Birds", in the second volume of which he summarized and modified A. R. Wallace's theory of the relation between nests and coloration of birds.  Elliott Coues wrote in the preface to the American edition of Dixon's book "Rural bird life" pointing out the originality of the observations made from the field and Julian Huxley noted Dixon for recognizing the value of prismatic binoculars for bird study.  In his later years, he wrote in the newspapers on agricultural fairs and horse shows. The Color of Truth is a book by Kai Bird, published by Touchstone Books in June 2000.  Subtitled "McGeorge Bundy and William Bundy: Brothers in Arms", it is a biography focusing on the Bundys' role in American foreign policy, especially in the progression of the Vietnam War. Carolyn Sherwin Bailey (October 25, 1875 – December 23, 1961) was an American children's author.  She was born in Hoosick Falls, New York and attended Teachers College, Columbia University, from which she graduated in 1896.  She contributed to the "Ladies' Home Journal" and other magazines.  She published volumes of stories for children like methods of story telling, teaching children and other related subjects, which include "Boys and Girls of Colonial Days" (1917); "Broad Stripes and Bright Stars" (1919); "Hero Stories" (1919); and "The Little Rabbit Who Wanted Red Wings" (1945).  She wrote "For the Children's Hour" (1906) in collaboration with Clara M. Lewis.  In 1947, her book "Miss Hickory" won the Newbery Medal. John Joseph Martin (October 19, 1922 – August 7, 1997 ) was educated as a mechanical engineer, receiving a Ph. D. from Purdue University in 1951.  He joined North American Aviation in 1951 and moved to the Bendix Corporation in 1953.  In 1960, he joined the Institute for Defense Analyses.  While on sabbatical at the Royal Aircraft Establishment in Farnborough, Hampshire, Martin wrote "Atmospheric Entry".  This book became the first and arguably the best in the open literature about designing reentry vehicles.  Sir Michael James Lighthill, who was Martin's host at the Royal Aircraft Establishment, wrote the foreword to Martin's book.  In 1969, Martin served as a science advisor to the US President.  During 1973-1974 Martin served as an Associate Deputy Director at the Central Intelligence Agency and later as Deputy Assistant Secretary of the US Air Force.  In 1984, Martin became an Associate Administrator at NASA. Martin Parks Burks (January 23, 1851 – April 30, 1928) (some sources give the date of his birth as 1850) was born in Bedford County, Virginia.  His father was Judge Edward C. Burks, who served on the Supreme Court of Appeals from 1876 to 1882.  Martin Burks attended Washington and Lee University when he was only fifteen years old.  He later entered the University of Virginia and graduated with a Bachelor of Law Degree.  In 1872, he was admitted to the bar and began practicing law in Bedford County in partnership with his father.  This partnership continued until his father became a member of the Supreme Court of Appeals.  The younger Burks remained in practice at Bedford until he returned to Washington and Lee in 1900 as a professor of law.  Three years later he was made dean of the law department where he stayed until he was elected to the Supreme Court of Appeals in 1917.  Judge Burks was on the court until he resigned on April 16, 1928, because of ill health.  He died shortly before his resignation became effective.  Because of his enthusiasm and extensive study of the law, Judge Burks wrote a monograph in 1893, which was published as Burks on Separate Estates.  This was adopted as a textbook by practically every law school in Virginia.  In 1913, his book on common law, Burks’ Pleading and Practice, was published.  It immediately became the authority to lawyers and jurists on the subjects it included, and it was also adopted as a textbook by the law schools in Virginia. Larchmound is a house in Olney, Illinois, which was the home of ornithologist and botanist Robert Ridgway from 1913 until his death.  The house was built in 1866; while its architecture does not entirely fit a specific style, its steep roofs suggest a Gothic influence.  Ridgway moved to the home in 1913; the home was his second in the Olney area, as he had previously spent two summers at Bird Haven north of the city.  While living at Larchmound, Ridgway wrote 27 of his published works, including three volumes of his most comprehensive book, "The Birds of North and Middle America".  Ridgway also conducted botanical research and planted tree specimens at both Larchmound and Bird Haven; while the land surrounded Bird Haven was inundated by a lake in 1970, many of Ridgway's original plantings survive on the remaining 2.69 acre at Larchmound. American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer is a biography of J. Robert Oppenheimer by Kai Bird and Martin J. Sherwin published by Alfred A. Knopf in 2005.  Twenty-five years in the making, the book was awarded the 2006 Pulitzer Prize for Biography or Autobiography.  It also won the 2008 Duff Cooper Prize, Chicago Tribune Best Book of the Year, and "Discover Magazine" Best Science Book of the Year. To See Every Bird on Earth: A Father, a Son, and a Lifetime Obsession is a book by Dan Koeppel first published in 2005.  It is about the author's relationship with his father Richard Koeppel, an obsessive "Big Lister" birdwatcher who had spotted over 7000 different species of birds at the time the book was written.  The book focuses on Dan Koeppel's attempts to understand the obsession that ruled his father's life.  It also examines the culture on highly competitive birders who travel the world making lists of their sightings, and discusses the history and rules of listing.  Richard Koeppel was diagnosed with cancer in 2000, which curtailed his birding and forced him to switch to butterflies found locally near his home on Long Island, New York.  He died of cancer-related causes on August 2, 2012. Kai Bird (born September 2, 1951) is an American author and columnist, best known for his biographies of political figures.  He won a Pulitzer Prize for "American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer".
Answer: the atomic bomb