 From the 1950s through the 1980s, Vassiliev worked with friend and collaborator Erik Bulatov as a children's book illustrator.They developed a unique style of illustration that combined realist painting with graphic elements, such as text.This "official" source of income provided the means and materials for Vassiliev to take part in the Soviet Nonconformist Art movement, also known as "unofficial" or "dissident" art.