Compare memoirs with private correspondence

Published private and official correspondence supplies a second viewpoint close to the events without being another retrospective autobiography. James Somerville's papers preserve what he wrote, including communications with Cunningham, while events and institutional problems were still current. Comparing those letters with Cunningham's later account moves the inquiry from general trustworthiness to a more precise measure of accuracy. The extended wartime letter also shows why documentary collections can be rich but demanding research sources rather than easy narrative reading. The example helps explain why double or triple citations let readers test an argument through multiple kinds of evidence.