Samuel Luke was the Parliamentary governor of Newport Pagnell from late 1643 to June 1645. Administrative practice was to keep letter books in which a clerk copied in and out letters, warrants, passes, safe-conducts, requisitions, notices etc. Five of the letter books for the period October 1644 to June 1645 have survived. There are 1615 items from the letter books published here. They include letters to and from Parliamentary commanders; Luke's family; the Eastern Association Committee; other governors and area commanders; Luke's own officers and some from other units; and royalist commanders on exchange of prisoners. The letter books reveal details of military life, supplies, royalist prisoners, desertions, effect of war on country life, the progress of the war and disposition of troops.

The book concludes with 261 reports from scouts from all over the country. Luke later lived at Cople and was a member of Parliament and in London during some of his governorship at Newport Pagnell.