The papers of Henry Harley Arnold (1886-1950) span the years 1903 to 1967, with the bulk of the items concentrated in the years of World War II (1940-1946). The collection is large and contains material on almost all aspects of Arnold's adult life. The most comprehensive documentation, however, covers Arnold's tenure as chief of the United States Army Air Corps (1938-1942), chief of the army air forces (1941-1942), and commanding general of the army air forces (1942-1946). These changes in nomenclature reflect the growth of the military air arm from a small auxiliary of the army in the 1930s to a massive semi-autonomous armed service in World War II which became formally independent of the Army in 1947. Arnold, one of the nation's earliest military pilots, built what became the modern United States Air Force, and his papers are a documentation of that creation.

The papers are divided into a number of series and subseries. Several of the subseries contain detailed indexes which were prepared contemporaneously by Arnold's military staff or later by personal assistants either to Arnold or his wife after he left active service. In some cases, documents on the same or similar subjects are found in different subseries. When Arnold's papers arrived at Library of Congress, large sections came in an arrangement devised by Arnold and his staff during the creation and use of the papers. It was judged best not to modify Arnold's arrangement because it reflected Arnold's use of the papers and because several of these sections came with detailed indexes providing excellent research access to this material.

The Family Papers series, 1922-1955, consists largely of correspondence between Arnold and his family during the 1930s and 1940s. Most of this correspondence deals with family affairs along with some family business activities.

The Journals and Notebooks series, 1908-1946, includes a few journals that go back to Arnold's earliest flying days and the army air corps. Of significant interest are Arnold's notebooks from World War II when he took part in several of the major wartime conferences of the Allied leadership. Arnold kept notes on those meetings in small pocket diaries. These notes were later transcribed, and Arnold often interspersed with the typed transcriptions documents relating to the events noted in the journals. Arnold's notes include both substantive remarks about the issues discussed as well as observations about the principal figures at the conferences and physical aspects of the trip. Among the key wartime conferences recorded in Arnold's journals are those of Roosevelt and Churchill at Placentia Bay in 1941, the 1943 Cairo conferences with Roosevelt and Churchill, the Teheran conference with Stalin, Churchill and Roosevelt, and the 1944 Roosevelt-Churchill conference at Quebec. Also present are journals Arnold kept for wartime inspection trips to Great Britain, China, North Africa and the Pacific theater.

The Correspondence series, 1907-1967, is divided into several subseries. The Chronological subseries consists largely of military correspondence, reports, memoranda, and other official documents. Among its earliest items are the 1911 reports of then Second Lieutenant Arnold on his training as a pilot by the Wright brothers aviation company. Also present are copies of letters from Wilbur and Orville Wright to Arnold in which the Wrights answer Arnold's technical questions about the aircraft the brothers were building for the army. By 1939 Arnold was a brigadier general in charge of America's growing but still small army air corps. His files for 1939 and 1940 are filled with reports by American military observers in Europe about the rapid evolution of German, French, and British aircraft and air warfare tactics under the pressure of combat. As one report noted, European fighter aircraft in 1940 were routinely equipped with guns whose firepower was several times that of existing American fighters. Under Arnold's command, America's military air arm quickly caught up with and then surpassed in lethality those of other nations. Present in Arnold's 1945 file is an 8 August 1945 report to him on the dropping of the atomic bomb that begins “ Hiroshima is no more.”

The Congratulatory and Condolence Letters subseries comprises files generally in chronological order for major events in Arnold's life.

The General Correspondence subseries is further divided into two parts. The first is an alphabetical file consisting largely of correspondence and other documents of a military or semiofficial nature from Arnold's World War II years, although correspondence about personal matters is also found. The second part of this subseries, a Serial file, 1946-1950, consists of files numbered 1 through 714. Access to these numbered files is provided by an index which lists personal names or private institutions with a designation of the numbered file in which relevant material can be found. The material in these files is a mixture of correspondence and other documents dealing with Arnold's professional and personal activities after his retirement.

The Personal Correspondence subseries includes material from the early 1930s and the period from 1943 to 1950. The material for 1930-1934 is largely professional correspondence dealing with aviation and army air corps activities. The files for 1943-1950 consists largely of documents dealing with Arnold's purchase and maintenance of a residential property in Sonoma, California, to which he retired after his World War II duties.

The Military File series is the largest in the collection and is extremely rich with material on all aspects of American military air activity in World War II: mobilization, organization, supply, weaponry, training, personnel, strategy, command, intelligence, and technology. Only the official records of the army air force exceed in abundance the resources offered by the Arnold papers for the study of American air warfare in World War II. Much of the material in the Military File series consists of copies of official records which can be found at the National Archives. What gives this collection research interest is that it consists of copies of those documents that Arnold or his staff regarded as of sufficient significance to cull from the flood of paper that passed through his office during World War II.

In the Military File, the first subseries, entitled the Decimal File, 1940-1945, consists of military documents, messages, correspondence, memoranda, and reports filed in accordance with a decimal filing system (similar to the Dewey decimal system) used by the army during World War II. Access to the material in these files in best sought by use of two card-file indexes. The first index is alphabetical by the name of an individual connected to the documents. The index gives the decimal files in which documents by or about that person can be found. The second index is alphabetical by subject, institution, or organization. The indexes are detailed, with the name index taking up containers 39-46 and the subject index containers 47-60. In addition to the decimal designation, some of the decimal files also have subject matter titles which have been included in the container listing of the Arnold Papers.

The Message File subseries consists of incoming and outgoing official cables and other messages between Arnold's headquarters and other offices during World War II. Most messages are filed alphabetically by subject, office, or the name of a frequent correspondent, Dwight Eisenhower, for example. This subseries also contains a chronological file of Arnold's incoming and outgoing messages filed under his name.

The Official File subseries includes military reports, memoranda, correspondence, and other documents designated by files numbered 1-287 and 516-540. Files 1-210 have subject matter titles in alphabetical order while files numbered 211-287 have geographic area titles in alphabetical order along with a few files for non-geographic military commands, ferrying command, for example. Files numbered 516-540 contain a variety of reports, logs, and extensive documentation deriving from the investigation of the Pearl Harbor attack and the role of the army air force in that disaster. Indexes are available for both of these numbered sequences. Files numbered 288-515 are not extant in the Arnold Papers.

The Reports subseries, 1913-1949, consists of official military reports related to air warfare topics. Some of the reports are printed or near-print reports while others are in manuscript form. General reports largely concern the overall status of American military air power. Specialized reports relate to a variety of topics, such as atomic energy, analytic studies of American air warfare campaigns during World War II, and estimates of German war potential.

The Subject File subseries, 1917-1950, deals with a wide variety of official, professional, and private matters, treating such diverse topics as “Elks in Mexico,” regarding the fraternal order of Elks, military aircraft production, 1938-1945, and the 1941 Argentia conference of Allied leaders in Newfoundland. Most of the files deal with important military affairs during World War II.

The Miscellany subseries, 1934-1951, of the Military File series also contains a variety of files, including a chronological file of army air force air adjutant general memoranda and messages; a chronological mail log for Arnold's office listing “to,” “from,” and the subject of correspondence; a chronological file of Arnold's military correspondence spanning 1934-1945, the bulk of which is concentrated during World War II and deals with a wide variety of military topics; and an extensive chronological log of incoming telephone calls, often with notes on the subject of the call. In addition to the telephone logs, this subseries also includes a number of transcripts of telephone conversations between Arnold and members of his staff with other officials. Files of official war communiques publicly released by military offices relate to the course of the war effort. A Personal File index for files numbered 1-50 is included but only files numbered 34-40 and 42 are present in the collection.

The Postmilitary File, 1946-1949, contains Arnold's extensive correspondence after his retirement. The correspondence is divided into two sets, “A” and “B,” and is filed alphabetically. Indexes are provided for both sets. This series also contains subject matter files on the B-36 bomber, atomic testing, and congressional hearings on aviation policy.

The Speeches and Writings series, 1923-1955, includes Arnold's extensive speeches and writings, most of which relate to aviation and military matters. Arnold had a clear sense that he was taking part in the creation of a powerful American air arm, and many of his speeches and essays reflect his sensibility about the history-making character of the events he was discussing. Also in this series are files related to his 1949 book his memoir of the army air force in World War II.

Among the Miscellany series, 1903-1963, are photographs, financial papers, and biographical material, printed material, and other items that further reflect Arnold's historical sensitivity, especially the material he collected about the early years of American military aviation. Included are photographs, lists and biographies of early pilots, contemporaneous print and near-print accounts of important events in military aviation history, and extensive scrapbooks.

The Jo Chamberlin File, 1941-1989, consists of scrapbooks containing memoranda, reports, speeches, military papers, printed matter, and other miscellaneous material reflecting Chamberlin's assignment to the Office of Information Services, Army Air Forces, and as an aide to Arnold. Included are drafts of reports to the secretary of war by the commanding general, Army Air Forces, with annotations by Arnold, speeches drafted by Chamberlin for Arnold, reports from the Aleutian Island Campaign, information regarding 'foo-fighters,' and writings on Chamberlin's trip to Germany in the waning days of World War II.

The Classified series consists of security classified items removed from the collection. Removal sheets for all such material can be found in the files from which the items were removed. When any item in this series is declassified, it is restored to its original file. Classified items are not included on the microfilm edition of the Arnold Papers prepared in 1995.