This series comprises the Board of Trade (BT) registers and indexes of letters received and of the minutes of the Board referring both to its trade and colonial papers between 1635 and 1787. It includes also the general registers of the colonial letters received in the Secretary of State's Office between 1810 and 1849, after which date the registers are arranged under the respective colonies. Early volumes give a brief account of the contents of the letters; later volumes note the correspondent's name, the date of reply and action taken.