The Liber Exoniensis, or Exeter Domesday, is usually abbreviated as Exon. or LE. It is a Domesday satellite text for most of circuit 2 - the five south-western counties - and the only one of the six circuit returns of Great Domesday to have survived. The Liber Exoniensis and Little Domesday are the only strictly contemporary satellite texts; all others are later copies.
Despite its name, a strong case has been made for the Liber Exoniensis being a Salisbury manuscript, created there in 1086 under the eye of Bishop Osmund of Salisbury, once royal chancellor and a notable bibliophile. The Liber Exoniensis and Domesday Book (SOM 2,9) both record a grant which the king 'acknowledged himself at Salisbury in the hearing of the bishop of Durham, whom he ordered to write down this grant of his in the records'. It has been plausibly argued that the 'records' here are probably the Liber Exoniensis itself.
The text is incomplete, only Cornwall and Devon being relatively intact. Substantial parts of Dorset and Somerset have survived; but only one manor in Wiltshire. Like several other satellites, the Exeter text provides important evidence about the material collected by the Inquest - notably about livestock - but omitted from Domesday Book itself.
Its main significance, however, is the part it has played in debates about the making of Domesday Book. Unlike the Inquisitio Comitatus Cantabrigiensis satellite, the Exeter Domesday is organised feudally, more feudally indeed than Domesday Book itself since the counties are subordinated to the Honours of tenants-in-chief. If Domesday Book had been organised in this way, the manors of each tenant-in-chief would have been listed as a single block for the entire country. This structure led V.H. Galbraith to argue that relations with his tenants-in-chief were always the principle concern of the king. They, not the geld, dictated the structure of Domesday Book.
For the Salisbury origin of the Liber Exoniensis, see Teresa Webber, 'Salisbury and the Exon. Domesday: some observations concerning the origin of Exeter cathedral MS 3500', English Manuscript Studies, 1100-1700, vol. 1, edited by Peter Beal and Jeremy Griffiths (1989), pages 1-18. There is an important note on the LE and its relationship to Great Domesday in the printed Phillimore volume for Devon (Exon. Introduction). Galbraith's hypothesis on the making of Domesday Book, first outlined in 1942, has dominated discussions of the making of Domesday since the Second World War; it is most fully expounded in The making of Domesday Book (1961). The debate on the making of Domesday Book has, however, recently been re-opened by David Roffe, Domesday: the Inquest and the Book (2000), who relegates the Liber Exoniensis to a minor role and re-emphasises the geld and the geographical organisation of the Inquest.