The assize records comprise two concurrent series of documents: the rolls of gaol delivery and pleas, the formal written-up proceedings of each assize session; the assize files, which comprise bundles and loose papers forming the working documents or real-time record of the assizes. The rolls are generally in good physical order. The files are in some state of physical and intellectual disorder.

The assize rolls comprise records of gaol delivery (criminal cases) and pleas or civil action (referred to as the general sessions of the pleas). Each roll typically comprises the record of an individual assize session, apart from those of the Elizabethan period which often contain the records of multiple separate sessions in a single roll. The covering dates are as follows:

- for gaol delivery: 1558-1566 [still to be catalogued]; 1572-4; 1577-79; 1581; 1583-91; 1593-6; 1600-1; 1603-6; 1608; 1610-13; 1619; 1621; 1642 (one entry only).

- for pleas: 1515-17; 1558-1566 [still to be catalogued]; 1572-9; 1581-91; 1593-6; 1600-1; 1603-6; 1608; 1610-13; 1619-25; 1627; 1629-42; 1645-6; 1650-9; 1661-4; 1666-1671; 1673-4; 1693; 1699-1704; 1706; 1714-1722; 1724-1725; 1733-4.

After the 1620s, the records of gaol delivery, where extant, are to be found in the assize files. The assize files commence in 1605. The files typically consist of a mixture of the following record types: examinations; depositions; recognizances; indictments; coroners' inquests; list of court officials; gaol calendars; related court papers. Some bundles have been labelled by regnal year or document type but, generally, the contents are in some disorder and have not yet been examined in detail due to their physical condition.

Except for the Commonwealth period, the records are mostly in Latin up to 1733. The following information has been recorded for each roll entry, where possible: name of defendant with any stated aliases, his/her occupation and place of abode; date of offence; details of offence in summary, including the names of other parties involved. Some archaic phrases or words have been retained in description, particularly for entries relating to trespass and trespass on the case or assumpsit.

The spelling of Christian names has been modernised, where possible; the spelling of surnames has been retained as found in the records, using the first spelling encountered in an entry. The spelling of major place names (towns and villages) has been modernised using ‘The Place-Names of Cambridgeshire and the Isle of Ely’ (English Place-Name Society, Vol. XIX, edited by P.H. Reaney) as a reference text. The spelling of minor place names, particularly fields and pieces of fen ground, has been retained as found in the records. Unless otherwise stated, all places are in the historic county of Cambridgeshire.

Square brackets are used to indicate uncertainty or to present additional information supplied by the cataloguer.