The collection by Kir Bulychev includes two stories about the adventures of Alisa Selezneva and her friends - “Ancient Secrets” and “Pashka the Troglodyte”. The first story tells how the class in which Alice is studying begins historical practice and each student chooses a mystery of the past for himself and tries to unravel it. Arkasha Sapozhkov goes to the Mesozoic era to find out why dinosaurs became extinct. In the distant past, he witnesses a space battle and the death of a starship. The mystery of the disappearance of dinosaurs turns out to be connected with this event. In the second story, Alice’s best friend Pashka Geraskin chooses the Stone Age for his historical research and, under the guise of an orphan, settles in a troglodyte cave. He tries to teach his fellow tribesmen new knowledge, he himself becomes a great hunter, gets involved in an ancient war and lets his tribe down. He faces the most difficult task - to save himself and unravel the mystery of the disappearance of the Neanderthals. The publication reproduces 95 illustrations by the most famous illustrator Kir Bulychev - Evgeny Migunov. Included in: Source: