Koestler was a leading British communist in the first half of the twentieth century. Like many other leading left-wing voices at that time (such as George Orwell) his enthusiasm for the USSR had given way to disillusionment at the excesses of Stalinism, with its purges and oppressions. He was personally acquainted with many of the party officials who had suffered imprisonment and death at Stalin's hands, and `DAN' was his literary response.
`DAN' follows the thoughts of Rubashov as he awaits his fate in prison. Rubashov was previously an important figure in the ruling party, a leading cog in the revolution and government of his country (unnamed in the book, but obviously representing the USSR). He had also personally denounced saboteurs and traitors, and was responsible for many purges. When he is, in turn, arrested, he is force to grapple with the rights and wrongs of the course the communist revolution has taken, and confront the battle between personal tragedy and historical necessity. His opinions and role are examined through his interactions with his interrogators (his former friend Ivanov and the menacing Gletkin), his cell neighbours and his memories.
`DAN' is very similar in themes (and story) to Orwell's `1984', although it is set very much in the real world. What sets it apart, however, is that its protagonist (Rubashov) is not a rebel or an opposition figure. Instead he is a willing supporter of the regime and, though his arrest and imprisonment causes doubts, he is able to rationalise his fate in terms of the ideology that he believed, and still believes in. Thus, despite his position as a victim of oppression, Rubashov is actually able to give a balanced account of the rights and wrongs of his fate, as far as party orthodoxy is concerned. This made `DAN' unique among the views of Stalinism I have read. Aside from this it is very readable, although bleak, and an important and informed comment on European history.