Patrick O’Farrell’s Harry Holland: Militant Socialist (1964) grew from a doctoral thesis completed in the mid-1950s, at the Australian National University, at the height of the Cold War. The circumstances of its creation are important to understanding the assumptions upon which the biography depends. Of Irish Catholic descent and from the Grey Valley, the birthplace of New Zealand’s first wave of revolutionary industrial unionism, O’Farrell had observed first-hand the unravelling of this radical and socialist impulse in the late 1940s and early 1950s as Cold War attitudes enveloped the political world. Interpreting the political career of Harry Holland from within the more intense Cold-War-Canberra environment brought a sharper edge to O’Farrell’s biography. The extent of this influence is made clear in Manning Clark’s detailed account of the oral examination of O’Farrell’s PhD preserved in his personal papers. A reassessment of Harry Holland’s role as leader from this perspective suggests a need to revisit the historical debate about the relationship between socialism and the New Zealand Labour Party.