Commissioned in 1944 by General Leslie Groves, head of the Manhattan Engineer District, the thirty-six volume history was “intended to describe, in simple terms, easily understood by the average reader, just what the Manhattan District did, and how, when, and where” according to general editor Gavin Hadden, a longtime civil employee of the Army Corps of Engineers.
The volumes detail the Manhattan Project’s activities and achievements in research, design, construction, operation, and administration, as well as contain extensive annotations, statistical tables, charts, engineering drawings, maps, photographs, and derailed indices.
The PIDB [Public Interest Declassification Board] congratulates the Office of Classification, the Office of History and Heritage Resources, and the DOE’s Office of Science and Technical information for completing all declassification reviews on these important histories. In particular, we are gratified that the DOE prioritized these histories for declassification.
The PIDB is also pleased that these records received a line-by-line declassification review, rather than being subjected to simple pass/fail determinations.
The history is arranged in thirty-six volumes grouped in eight books. Some of the volumes were further divided into stand-alone chapters. Several of the volumes and stand-alone chapters were never security classified. Many of the volumes and chapters were declassified at various times and were available to the public on microfilm. Parts of approximately a third of the volumes remain classified.
The Office of Classification and the Office of History and Heritage Resources, in collaboration with the Department’s Office of Science and Technical Information, have made the full-text of the entire thirty-six volume Manhattan District History available on this OpenNet website. Unclassified and declassified volumes have been scanned and posted. Classified volumes were declassified in full or with redactions, i.e., still classified terms, phrases, sentences, and paragraphs were removed and the remaining unclassified parts made available to the public. All volumes have been posted.