The Russian Revolution aimed to dissolve the family. Neither true equality nor true freedom could be achieved, the Bolsheviks argued, until class bonds trumped all other loyalties—that is, until people no longer felt greater responsibility toward their family than they did toward strangers. “The worker-mother must learn not to differentiate between yours and mine,” Alexandra Kollontai, the Soviet Union’s first people’s commissar for social welfare, wrote. “There are only our children, the children of Russia’s communist workers.” The early government “tried its best to separate the children from the family,” as Leon Trotsky later wrote, “in order thus to protect them from the traditions of a stagnant mode of life.” This radical attempt to dilute and deny family attachments is the specter haunting The Hill, a remarkable debut novel by Harriet Clark. The author is the daughter of Judy Clark, a onetime member of the American Marxist militant group known as the Weather Underground. Judy, a single mother, left 11-month-old Harriet at home when she drove the getaway car in a 1981 robbery of an …