| # | Cat. | Reference | Title | Year | |
|---|---|---|---|---|---|
| 1 | A/V | 3-9602243 | [Isador Caplan at B-P Library -- Commentary on legal documents] | - | |
| 2 | Art | 5-9500021 | Isador Caplan | 1993 | |
| 3 | Arch | BBA/CAPLAN_I | Correspondence between Benjamin Britten and Isador Caplan | 1961 | |
| 4 | Arch | CLM/7/46 | Correspondence from Isador Caplan | 1985 | |
| 5 | Arch | CRS/3/119 | Correspondence to Joan Cross from Isador Caplan | 1989 | |
| 6 | Arch | CRS/18/1/3/9 | Correspondence to Joan Cross from Isador Caplan | 1971 | |
| 7 | Arch | GSF/6 | Posthumous correspondence between Donald Mitchell and Isador Caplan | 1969 | |
| 8 | Arch | HOL/2/8/1/2 | Correspondence from Imogen Holst to Isador Caplan | 1981 | |
| 9 | Arch | HOL/2/8/1/2/1 | Note from Imogen Holst to Isador Caplan | 1981 | |
| 10 | Arch | HOL/2/8/1/2/2 | Letter from Imogen Holst to Isador Caplan | 1981 | |
| 11 | Arch | HOL/2/8/1/2/3 | Letter from Imogen Holst to Isador Caplan | 1982 | |
| 12 | Arch | HOL/2/8/1/2/4 | Letter from Imogen Holst to Isador Caplan | 1982 | |
| 13 | Arch | HOL/2/8/1/2/5 | Letter from Imogen Holst to Isador Caplan | 1982 | |
| 14 | Arch | HOL/2/8/1/2/6 | Letter from Imogen Holst to Isador Caplan | 1982 | |
| 15 | Arch | HOL/2/8/2/41 | Correspondence from Isador Caplan to Imogen Holst | 1976 | |
| 16 | Arch | HOL/2/11/8/17 | Photograph of Donald Mitchell and Isador Caplan | 1985 | |
| 17 | Arch | HOL/2/11/9/1 | Photographs of Isador Caplan, Nina Holst, Rosamund Strode and Theodore Holst outside 9 Church... | 1991 | |
| 18 | Arch | HOL/2/11/9/2 | Photograph of Isador Caplan, Nina Holst, Helen Lilley and Theodore von Holst outside 9 Church... | 1991 | |
| 19 | Arch | HOL/2/11/9/3 | Photographs of Isador Caplan, Nina Holst and Theodore Holst inside 9 Church Walk | 1991 | |
| 20 | Arch | HOL/2/11/9/4 | Photograph of Isador Capland and Theodor Holst inside 9 Church Walk | 1991 | |
| 21 | Arch | HOL/2/11/10/20 | Photograph of Imogen Holst, Lyla Orbiston and Isador Caplan | 1981 | |
| 22 | Arch | HOL/2/22/4/16 | Isador Caplan and Len Haswell interviews | 1988 | |
| 23 | Arch | HOL/4/3/1/14 | Correspondence with Isador Caplan | 1989 | |
| 24 | Arch | HOL/5/2/13 | Isador Caplan interview transcript | 1988 | |
| 25 | Arch | HOL/6 | Isador Caplan | 1977 | |
| 26 | Arch | MSC2/2/8 | Letter from Isador Caplan to George Behrend | 1977 | |
| 27 | Arch | MSC63/2/10/3 | Photograph of Britten with Joan and Isador Caplan in Red House garden | 1966 | |
| 28 | Arch | MSC63/2/10/10 | Photograph of Isador Caplan and Donald Mitchell | 1966 | |
| 29 | Arch | MSC98 | Isador Caplan and Britten | 1945 | |
| 30 | Arch | PH/4/550A | Benjamin Britten with Isador Caplan | 1976 | |
| 31 | Arch | PHF/1978/90 | Photograph of Jenni Vaulkhard, Isador Caplan, Sir Eugene Melville and Mstislav Rostropovich... | 1978 | |
| 32 | Arch | PHF/1981/63 | Photograph of Imogen Holst, Lyla Osbiston and Isador Caplan | 1981 | |
| 33 | Arch | PPA/CAPLAN_I | Correspondence between Peter Pears and Isador Caplan | 1946 |
