Mainly during foreign or academic tours. Although Lady Whitby accompanied Sir Lionel on some trips after the end of the Second World War, some of these diaries were written for each other, when separated by foreign travel and work, with the intention that they could read them when reunited. The diaries cover the latter part of the Second World War, when Dr Whitby was Commanding Officer of the Army Blood Transfusion Service, and his time as Regius Professor of Physic at the University of Cambridge and Master of Downing College (1947-56).