Andrew R.B. Ferguson is Research Coordinator at Optimum Population Trust, 11 Harcourt Close, Henley-on-Thames, RG9, 1UZ, United Kingdom (email:andrewrbferguson@hotmail.com). He is also editor of the biannual OPT Journal. His special interests include applying eco-footprinting to estimating national carrying capacities, assessing the net energy capture of renewable energy sources, and raising awareness of the existence of Clive Pointing's seminal book, A Green History of the World (1991). In an earlier stage of his career, he was an airline pilot (1957-1983).