Witness, first published in May 1952, is a best-selling book of memoirs by American writer Whittaker Chambers (1901–1961), which recounts his life as a dedicated Marxist-communist ideologist in the 1920s, his work in the Soviet underground during the 1930s, and his 1948 testimony before the US Congress, which led to a criminal indictment against Alger Hiss and two trials in 1949.

[1][2] What became the "Hiss Case" started on August 3, 1948, when Whittaker Chambers appeared under subpoena before the US House Un-American Activities Committee (HUAC) and testified about his work in the Soviet underground, including service in the mid-1930s as courier between Soviet handlers in New York and members of the Ware group, a network of US federal officials whose primary purpose was to infiltrate government but also to obtain intelligence.

On December 15, 1948, US Department of Justice indicted Alger Hiss on two counts of perjury as part of a related grand jury investigation.

[1] As early as December 16, 1948 (the day after the Hiss indictment), Chambers received the first offer for a memoir – from William Phillips, publisher of Partisan Review (a leftist, anti-Stalinist journal), followed by British MP Richard Crossman (for contribution to The God That Failed, published in 1949), and David McDowell of Random House (and friend of Chambers' friend and colleague, James Agee.

Foster, Chambers accepted orders to go into what he believed was the Party's underground but turned out to be Soviet-controlled espionage that involved the Ware group, of which Alger Hiss was a member.

[1] The memoir spends less than ten pages[1] on the two trials of Alger Hiss – which by that time had already received coverage in newspaper, magazines, and radio, as well as serving as the main subject of two books published in 1950: Seeds of Treason by conservative journalists Ralph de Toledano and Victor Lasky[4] and A Generation on Trial by liberal journalist Alistair Cooke (later host of Masterpiece Theater).

[5] While many events in the book predate the Cold War and McCarthyism, other events occur after the start date of the Cold War (March 12, 1947 – the Truman Doctrine), while US Senator Joseph McCarthy cited the Hiss Case in his famous first "Enemies Within" speech in Wheeling, WV, on February 9, 1950, which followed less than two weeks after the conviction of Alger Hiss.

His wife Esther Shemitz and former colleague Duncan Norton-Taylor chose, edited, and assembled portions of the follow-on book plus diary entries, poetry, and other writings, published as Cold Friday in 1964.