•1 box of correspondence with The Royal Scottish Arboriculture Society
•1 box of correspondence with the Annals of Botany
•1 box of correspondence with The University of Glasgow
•1 box of correspondence with Sir David Prain(1857-1944)
•2 boxes of correspondence regarding the Rodriguez (Transit of Venus) Expedition (1874) Papers
•5 boxes of correspondence including miscellaneous papers, reprints, lectures and drawings, regarding Socotra
•26 boxes and 1 book of correspondence with various people and organisations
•2 boxes of miscellaneous personal papers
•1 box of miscellaneous papers regarding applications for chairs
•2 boxes of miscellaneous lectures and lecture notes
•1 box of miscellaneous notes, extracts, reports and addresses
•1 box of plant lists and local plant names
•1 box of post-retirement correspondence with Sir William Wright Smith(1875-1956)
•1 box of miscellaneous papers, reprints and notes
•1 box of papers regarding the Botanic Society Edinburgh Billets 1836-76 (Isaac Bayley Balfour’s personal copies)
•1 box of various distribution maps and schematic drawings
•4 boxes Isaac Bayley Balfour 'grandfather’s' papers and notes [I believe 'grandfather is likely Isaac Bayley Balfour, and it's how the donor referred to him, as opposed to it being IBB's grandfather] - to one of these boxes ("box 8 of 16") has been added (June 2019) an auction catalogue from Dulau and Co. Ltd. "Recent Useful Gardening Books"; "Botanical & Horticultural Works from the libraries of the late Sir Isaac Bayley Balfour FRS, C. Harman Payne FRHS, William Watson of Royal Botanic Gardens, Kew and other sources" No. 132, Part I, October 1925.
•1 box of M/S papers – monograph on figures
•1 folder of a collection of original drawings by John Nugent Fitch(1849-1927), for Botany of Socotra
•Personal diary of a visit to Socotra in 1880
•1 box of reprints and correspondence regarding Socotra
•I.B. Balfour ‘New Species of Rhododendron’ (copy belonged to G. Forrest so filed in the Forrest collection)
•3 letters dated 1877 -1878 from Joseph Decaisne, to I. Bayley Balfour filed with “Balfour, I. Bayley” correspondence under “Decaisne, J”
Correspondence from Archibald Dickson, (brother of Prof. Alex. Dickson, Regius Keeper 1880 -87) re: late brother’s affairs dated 1889 filed with “Balfour, I. Bayley” correspondence under “Dickson, Archibald”
