There lived two most ordinary boys in the world. Even their names were unremarkable: Vasya Golubev and Yurka Boytsov. Once Vasya went in search of a mammoth tooth, and Yurka, together with his faithful dog Sharik, ran away from home - and that’s when their incredible adventures began. Vasya, for example, had a chance to visit the distant future, make friends with a living mammoth and find himself on March 33rd. And Yurka got on a real spaceship and met his peers from another civilization. But none of the boys suspected that another adventure lay ahead, in which both of them would have to participate... The trilogy of Vitaly Melentyev is one of the most famous works of Soviet children's fiction. An exciting story about the adventures of two ordinary schoolchildren teaches us that for both aliens from other worlds and for future generations of earthlings, courage remains courage, honesty remains honesty, and true friendship knows neither time nor distance. The colorful world of the fantasy trilogy is reflected in their lively, memorable illustrations by the masters of Soviet and Russian book graphics - Anatoly Eliseev and Mikhail Skobelev.