1. IOR/R/20/B/1-3459 Reference (shelfmark): IOR/R/20/B/1-3459 Title: Civil Secretary and Chief Secretary's Records Collection Area: India Office Records and Private Papers Languages: English Date Range: 1936-1965 Extent: 3447 files
2. IOR/R/20/B/1-1060 Reference (shelfmark): IOR/R/20/B/1-1060 Title: Civil Secretary: Ordinary files Collection Area: India Office Records and Private Papers Languages: English Date Range: 1936-1942 Extent: 1061 files
3. IOR/R/20/B/2000-2077 Reference (shelfmark): IOR/R/20/B/2000-2077 Title: Chief Secretary: Ordinary files Collection Area: India Office Records and Private Papers Languages: English Date Range: 1941-1957 Extent: 78 files
4. IOR/R/20/B/2078-2110 Reference (shelfmark): IOR/R/20/B/2078-2110 Title: Chief Secretary: Secret files Collection Area: India Office Records and Private Papers Languages: English Date Range: 1941-1958 Extent: 29 files
5. IOR/R/20/B/2150-2339 Reference (shelfmark): IOR/R/20/B/2150-2339 Title: Chief Secretary: Lands files Collection Area: India Office Records and Private Papers Languages: English Date Range: 1941-1963 Extent: 189 files
6. IOR/R/20/B/2781-3382 Reference (shelfmark): IOR/R/20/B/2781-3382 Title: Chief Secretary: Secret files Collection Area: India Office Records and Private Papers Languages: English Date Range: 1958-1964 Extent: 602 files
7. IOR/R/20/B/3445-3459 Reference (shelfmark): IOR/R/20/B/3445-3459 Title: Chief Secretary: Ordinary files Collection Area: India Office Records and Private Papers Languages: English Date Range: 1960-1965 Extent: 15 files
8. IOR/R/20/B/2111-2149 Reference (shelfmark): IOR/R/20/B/2111-2149 Title: Chief Secretary: Most secret files Collection Area: India Office Records and Private Papers Languages: English Date Range: 1941-1955 Extent: 38 files
9. IOR/R/20/B/2340-2376 Reference (shelfmark): IOR/R/20/B/2340-2376 Title: Chief Secretary: Intelligence Summary files Collection Area: India Office Records and Private Papers Languages: English Date Range: 1941-1952 Extent: 37 files
10. IOR/R/20/B/2654-2679 Reference (shelfmark): IOR/R/20/B/2654-2679 Title: Chief Secretary: Secret Protectorate files Collection Area: India Office Records and Private Papers Languages: English Date Range: 1944-1955 Extent: 128 files