The title of the first edition in 1833 expressed its scope clearly: A Genealogical and Heraldic History of the Commoners of Great Britain and Ireland, enjoying Territorial Possessions or High Official Rank, but uninvested with Heritable Honours.

At the time the series started, the group it covered had considerable political, social and economic influence in their localities and in some cases nationally.

[4] A review of the 1952 edition in Time noted: Landed Gentry used to limit itself to owners of domains that could properly be called "stately" (i.e. more than 500 acres or 200 hectares).

There was then a paragraph on the owner of the property, with his coat of arms illustrated, and all his children and remoter male-line descendants also listed, each with full names and details of birth, marriage, death, and any matters tending to enhance their social prestige, such as school and university education, military rank and regiment, Church of England cures held, and other honours and socially approved involvements.

Professional details were not usually mentioned unless they conferred some social status, such as those of civil service and colonial officials, judges and barristers.

Advertisements for the 1894 edition stated: "Apocryphal statements, which had crept into former editions, have been expunged, erroneous particulars and incorrect descents discovered and omitted..."[7] This dedication to accuracy reached its peak under the chief editorship, from 1949 to 1959, of L. G. Pine – who was very sceptical regarding many families' claims to antiquity: 'If everybody who claims to have come over with the Conqueror were right, William must have landed with 200,000 men-at-arms instead of about 12,000',[8] – and Hugh Massingberd (1971–83).

The Ireland edition is important for genealogists, because it includes not only the Old English (12th century onward arrivals) and the New English families (16th century onward arrivals), but also some of the leading elements of the Gaelic Irish families who previously ruled vast swathes of Ireland and maintained some influence, including the O'Briens, the O'Conors, the MacCarthys, the Kavanaghs, and more.