The Sikh Reference Library was housed within the Golden Temple complex and held manuscripts, hukamnamas bearing the Gurus' signatures, rare printed books, and the records of the Sikh institutions.
It was lost during Operation Blue Star in June 1984. Accounts differ as to whether it burned during the fighting or was removed by the army afterward. The army has at various times acknowledged taking material and returning some of it.
Partial returns were made in the 1980s and 1990s. What was returned, what was destroyed and what remains held has never been fully accounted for. The SGPC has asked repeatedly and received partial answers.
Estimates of the number of manuscripts lost run into the thousands, including handwritten birs and correspondence from the eighteenth century.
It is the largest single loss of Sikh documentary heritage in modern times and there is no agreed inventory of what was in the building on the day.
It held manuscripts, hukamnamas, rare books, photographs and the papers of the Singh Sabha and Akali movements, built up over decades inside the complex.
It was destroyed in June 1984. Material was removed by the army before the fire, and the question of what was taken, what was returned and what was lost has never been resolved.
Items have been handed back in batches over the decades since. There is no published inventory of what the library held, which means the loss cannot be measured.