This series contains the original SOE general file index, listing for each indexed subject original SOE file references.
The index also contains nominal references, which include other details than the relevant file references: typically any aliases used by the subject, the subject's occupation or function, nationality, details of circuits subjects in the field worked with, the subject's contacts in the field, sometimes with location or address details, and indications of operations undertaken. The date of birth field on the card is almost never completed. In volume, nominal index cards greatly exceed subject ones.
Since the reorganisation of the SOE archive in the 1960s, it is no longer possible, without extensive investigation and speculation, to identify current piece numbers from these file references. Nevertheless, these index cards give the last remaining references to headquarters files which no longer survive.
The cards include occasional post-war additions by successive SOE Advisers, including indications that the file referred to was now 'missing', and sometimes, for individuals, dates of death or other biographical information.
The two types of card, subject and nominal, use for the most part different forms of printed card, and it seems likely that this index was originally two separate indeces which were, at some unknown time in the past, merged.