He was the leader of the Workers World Party from 1959-1989.
He was a member of the CPUSA until the 1940s and joined the SWP which he left in 1956 because of the Hungarian Revolution which was supported by the SWP while Macy supported soviet intervention.
The Workers World Party was characterized by outspoken defense of all Communist governments in the world.
During the Russian Civil War, his family was a target of pogroms by the White movement and received protection from the Communist forces. They resettled in Brooklyn.
This is actually 2 books in one -- also included was Vince Copeland's "The History of USSR-China Relations", which I'll add on here individually because it's a long read in its own right.
Sam Marcy is the founder of Workers World Party, the Communist Party I belong to, and while I obviously am in agreement with him on topics such as the National Question, Black Liberation, and the rise of high tech capitalism, I find myself questioning some of his statements here RE: Stalin. There's no doubt that Marcy was a trotskyist early on, and WWP itself carried a trot line in its early days -- thankfully we've gone far, far away from that and embrace Marxism-Leninism, and Stalin. Trotsky is important in his own right; he contributed some very important factors to the Bolshevik Revolution, but Trotsky's idea of "permanent revolution" and the line of "only developed countries can lead socialism" is perhaps one of the most backwards, colonialist, and reactionary lines I can think of. Fortunately by this point, Marcy seems to have abandoned Trotskyism, but his insistence of a "bureaucratic USSR" under Stalin is also something I question.
Certainly I am anti-Khrushchev; I am one of those who believe that Soviet revisionism began with Khrushchev and put the USSR on a collision course with a capitalist coup, which is exactly what happened less than 40 years after Stalin's death. I don't necessarily believe that the USSR was ever "social-imperialist" or "social-fascist" during these decades between 1953 and 1991, but I do believe that the revisionist line that the USSR took, Khrushchev all the way up to Yeltsin, allowed imperialism and fascism to deplete the Party and the masses of a true revolutionary line that, if avoided, could have resulted in the USSR still existing today [it does not, for all of you #BlueWave jackasses who think Putin is a secret Communist -- he isn't]. Stalin may have made errors in not fully believing the Chinese Communist Party could succeed in a Revolution; the Bolsheviks took 12 years to lead a revolution, the CCP took 28 years -- that does not make them "less revolutionary", in fact it made the conditions for a revolution very ripe, but I don't find it hard to believe that Stalin after a certain point started to doubt it. Of course he was incorrect! But once he saw the strength of the CCP, and the absolute iron-willed discipline and determination, he formed a bond with socialist China that was ultimately unbreakable, as Marcy and Copeland write in their respective pieces here. That bond carried on even through the Sino-Soviet split, the revisionism of the USSR, and up til its dissolution in 1991.
Despite my criticisms (and I intend this to only be a criticism, not a bashing; Sam Marcy was a brilliant man, Marxist thinker, and revolutionary who is responsible for many great things -- he has also been dead over 20 years and "bashing" him would just make me look ridiculous in this instance), I appreciate Sam Marcy's overall point that despite the Sino-Soviet split, despite the shortcomings even in China that took place in the last years of Mao's life, with richard nixon and all, he still holds the line that Workers World Party proudly holds today: solidarity with all socialist nations fighting against u.s. imperialism, capitalism, and colonialism.
This is a fantastic read to challenge yourself and challenge other Marxist thinkers on the Sino-Soviet split and the history leading up to it. Don't take my criticisms as "I hated this"; I thoroughly enjoyed it. It's a great exercise in study.