From its first edition to its last, it was presented by Alistair Cooke, who would speak of a topical issue in the US, tying together different strands of observation and anecdote and often ending on a humorous or poignant note.
The series ran from 24 March 1946 to 20 February 2004, making it the longest-running speech radio programme hosted by one individual.
A prototype, Mainly About Manhattan, was broadcast intermittently from October 1938, but the idea was shelved with the outbreak of World War II in 1939.
The first American Letter was broadcast on 24 March 1946, initially confirmed for only 13 installments, after Cooke had given a one-off talk under that title in the series Sunday Newsletter on 25 November 1945.
In March 2014, the BBC announced it had recovered over 650 lost editions of the programme, recorded by two listeners, Roy Whittaker in Cornwall and David Henderson in Warwickshire.