Socialism has been one of the most popular political ideas in history, rivaling in some ways even the great religions. By the late 1970s, a mere 150 years from the time the term socialism was coined, roughly 60 percent of the world population was living under governments that called themselves "socialist," although these varied widely in their institutions and were often violently at odds with one another.

Socialism drew impetus from the rise of industry in Europe in the nineteenth century. The new wealth generated by new methods of production encouraged the belief that now it would be possible to assure a comfortable standard of living for every member of society. The uneven distribution of this new wealth was seen to pose ethical questions that were less often asked about long-entrenched class disparities prevalent in the countryside. Socialism was seen by many of its advocates as not only an ethical...