  But it is an enigma to which the twenty-first century seems increasingly drawn. The year of his centenary, 2012, witnessed numerous conferences, publications, and cultural events in his honor. Some reasons for this explosion of interest are obvious. One is that the question of the power and limitations of computation now arises in virtually every sphere of human activity. Another is that issues of sexual orientation have taken on a new importance in modern democracies. More subtly, the interdisciplinary breadth of Turing's work is now better appreciated. A landmark of the centenary period was the publication of Alan Turing, his work and impact (eds. Cooper and van Leeuwen, 2013), which made available almost all aspects of Turing's scientific oeuvre, with a wealth of modern commentary. In this new climate, fresh attention has been paid to Turing's lesser-known work, and new light shed upon his achievements. He has emerged from obscurity to become one of the most intensely studied figures in modern science.