Oleg Pen"kovskii (Penkovsky, 1919-1963), a Russian intelligence officer, was tried and sentenced to death for spying for the USA and Great Britain in 1963. Grevill Vinn, an English businessman, was his connection. This book is based on three documentary sources: Pen"kovskii"s notes; an official report about Pen"kovskii"s trial in Moscow in 1963; and reports in the press.