It was noted above that key individuals have often played an important role in driving research. Disputes between individuals have also been an important motor for research – such as the controversy over the finds from crannogs on the Clyde, subsequently revealed as modern fakes (Hale & Sands 2005), or views on the evidence of material culture as indicators of contacts and chronology (MacKie 1965a-b, 1971; cf Clarke 1970, Lane 1987). Brochs and related complex drystone architecture has been a long-running source of controversy, from the disagreements between Anderson and Ferguson in the late 19th century (Anderson 1877; Ferguson 1878), the debates between Scott and Graham in the mid 20th century (Scott 1947, 1948; Graham 1947), Harding versus MacKie in more recent years (e.g. Harding 1984, 2000a; MacKie 1965a-b, 1983, 1994, 2008, 2010), and debates between the Edinburgh and Sheffield/Cardiff field projects on the Western Isles (Parker Pearson et al. 1996; Armit 1997a, 1997b; Sharples & Parker Pearson 1997; Gilmour & Cook 1998). This vibrancy of debate and variation of opinion has been important feature in keeping the subject fresh, although at times the debate has become a little self-absorbed.