About the book: 2017 / "Children's Library" - a series of excellent children's books with incredible stories, fairy tales and short stories. The fiftieth volume includes two stories B . Raevsky and A. Sofin. “In the footsteps of M.R.” In a small wooden case there were yellowed sheets of paper covered with pencil notes. Leningrad archaeologists made such a find in one of the caves of Dauria. Who is he, the author of the half-decayed diary, this mysterious M.R.? Genka, the son of the archaeologist Bashmakov, together with his friends decides to solve this mystery. Dozens of people help the Red Pathfinders in their search... “Big Bertha” The second story tells how the Pathfinders unravel the no less mysterious story of the appearance and disappearance of the giant German cannon “Big Bertha” on the Leningrad Front».