This four volume set contains the biographies of 3,175 individuals who sat in the House of Commons in the late 14th and early 15th centuries, providing not only a picture of political affiliations, aim and motives in seeking Membership, but also a study of other preocupations: the contrast between the code of chivalrous conduct and the reality of military service; the competitive pursuit of wealthy heiresses; the sometimes ambivalent relations between the laity and the Church; and their fluctuating success and failures in the scramble for patronage and preferment from the Crown and baronetage alike.

Among those included are poets (Geoffrey Chaucer made an appearance in 1386), pirates (such as the notorious William Long and John Hawley), lollards (including Sir John Oldcastle, who met a traitor's death), henchmen of the king (most notably the infamous Bussy, Bagot and Green) and the most outstanding parliamentarians of the Middle Ages, among them Sir John Tiptoft, perhaps the youngest Speaker ever to be elected, the charismatic Thomas Chaucer (the poet's son), and the intrepid Sir Arnold Savage, whose verbal exchanges with Henry IV throw fresh light on the relationship between King and Commons in the 15th century.

Surveys of each of the 135 constituencies represented in Parliament in this period supply a detailed explanation of local politics, while information about the economic and constitutional background of each city and borough provides the context in which the MPs' biographies are set. The Introductory Survey in Volume I, the culmination of a lifetime's dedication to the subject by the distinguished historian J. S. Roskell, provides the most thorough examination yet undertaken of the work of the medieval House of Commons. Appendices supply tables on specific topics discussed in the Introductory Survey and touched on in the biographies.