“Improper Names” offers a genealogy and theory of the improper name, which author Marco Deseriis defines as the adoption of the same pseudonym by organized collectives, affinity groups, and individual authors. Although such names are often invented to pursue a specific social or political agenda, they are soon appropriated for different and sometimes diverging purposes. This book examines the tension arising from struggles for control of a pseudonym’s symbolic power. Deseriis provides five fascinating and widely varying case studies. Ned Ludd was the legendary and eponymous leader of the English Luddites, textile workers who threatened the destruction of industrial machinery and then advanced a variety of economic and political demands. Alan Smithee an alias coined by Hollywood film directors in 1969 in order to disown films that were recut by producers became a contested signature and was therefore no longer effective to signal prevarication to Hollywood insiders. Monty Cantsin was an open pop star created by U.S. and Canadian artists in the late 1970s to critique bourgeois notions of authorship, but its communal character was compromised by excessive identification with individual users of the name. The Italian media activists calling themselves Luther Blissett, aware of the Cantsin experience, implemented measures to prevent individuals from assuming the alias, which was used to author media pranks, sell apocryphal manuscripts to publishers, fabricate artists and artworks, and author best-selling novels. The longest chapter here is devoted to the contemporary hacktivist group known as Anonymous, which protests censorship and restricted access to information and information technologies. After delving into a rich philosophical debate on community among those who have nothing in common, the book concludes with a reflection on how the politics of improper names affects present-day anticapitalist social movements such as Occupy and 15-M.