In the depths of the Great Crystal" is a cycle of fantastic stories by Vladislav Krapivin, united by a common picture of a metauniverse, shaped like a crystal, each face of which is a separate universe, and partially overlapping plots. The leading role in the works of the cycle is played by children who have special abilities that allow them, in particular, to penetrate parallel universes. A special role is given to a certain community of Guardians - Commanders, called upon to protect such children. The image of the Commander is Krapivin’s most interesting find in the works of the cycle, the source of which is probably the life experience of the writer, who in the 1960-1980s led the pioneer detachment “Caravella”. Using the example of a fictional world, the author examines the problems of the real world - homelessness, violence against children and their protection from arbitrariness. Another leitmotif of the works in the cycle is the relationship between mother and child, children’s longing for parents from whom they are somehow separated, problems of relationships in single-parent and broken families.