This is an artificial collection of rare and unpublished recordings featuring music by Charles Ives, created as part of a project funded by the Grammy Museum in 2017 to digitize and preserve these recordings. The majority of the recordings were unprocessed materials within Historical Sound Recordings (HSR) that had been acquired over time through various donations. These recordings were pulled from their storage locations (predominantly ML 102M, HSR Studio and B20B Basement) into this artificial collection. However, a number of recordings were also pulled from boxes 74, 75, 76, 80, 82, and 83 of The Howard and Helen Boatwright papers (MSS 93), a collection that was only minimally processed at the time this artificial collection was created. Notes have been added to the aforementioned boxes from the Boatwright Collection, in addition to the relevant item records in this finding aid, detailing this decision and ensuring the original provenance of these items is well documented. Finally, a small number of items included in this finding aid, that were also part of the digitization project funded by the Grammy Museum in 2017, are in fact part of different collections, namely the Richard C. Burns Archive of Overtone Records (MSS 104) and Yale School of Music Tapes (HSR 4). The Richard C. Burns Archive of Overtone Records collection is fully processed. However, the finding aid for the collection currently only exists in paper form. It was decided that these materials should be included in this artificial collection in order to improve access, but that if and when the finding aid for the Richard C. Burns Archive of Overtone Records collection was added to ArchivesSpace, these items would be removed from this artificial collection. The Yale School of Music Tapes are technically on deposit with the Gilmore Music Library. The Yale School of Music maintains documentation on the location of each recording in the collection. However, no finding aid exists for the collection. It was decided that these materials should therefore remain in their existing collection but again be included in this finding aid to improve access.