★ Ren Hirayama is a professor at Waseda University‘s School of International Liberal Studies and holds a PhD in Science. He published the paper “Oldest known sea turtle” in Nature and participates in fossil excavation surveys in Kuji City, Iwate Prefecture. The book includes the latest excavation information.
★ The “So Interesting You Can’t Sleep” series has sold over 700,000 copies. This is not simply a book that “tells you what dinosaurs looked like,” but one that starts from tiny clues left in fossils and reasons step by step to reveal how dinosaurs looked and lived—letting readers enjoy the pleasure of solving a mystery.
★ “Dinosaurs are ‘birds that don’t fly’.” “There are carnivorous dinosaurs but no herbivorous dinosaurs.” “Tyrannosaurus only hunted when young.” The book presents multiple views that overturn common knowledge, each supported by fossil evidence and reasoning, not speculation.
★ For readers who loved dinosaurs as children and remain interested in paleontology as adults—no professional background needed, only curiosity.

Dinosaurs are popular in every era.

Although they are ancient creatures that went extinct long ago, how can we know what dinosaurs looked like and how they lived? That is because researchers reason based on the tiny clues left in fossils, comparisons with living animals, and analysis using scientific techniques.

While many books simply tell readers “this dinosaur looked like this and lived like this,” this book, by a leading dinosaur researcher, starts from known clues and reasons step by step, allowing readers to enjoy the pleasure of solving a mystery.

In this paperback edition, two new chapters have been added on the mysteries of sauropods: “Why were they so big?” and “The size and position of their nostrils.”

A leading dinosaur researcher takes on the challenge of solving mysteries! Tyrannosaurus only hunted when young. Stegosaurus protected itself by looking scary. They were originally like birds—so why did they become like reptiles? Dinosaurs were not intelligent enough to be social. Japanese dinosaur research is on track.

Ren Hirayama（平山廉）
Professor at Waseda University‘s School of International Liberal Studies. PhD in Science (Kagoshima University). Born in 1956 in Tokyo. Graduated from Keio University Faculty of Economics; withdrew from the doctoral program at Kyoto University Graduate School. After serving as a lecturer at Teikyo University of Science and Technology and an associate professor at Teikyo Heisei University, he assumed his current position. Specializes in fossil reptiles, with a particular interest in the phylogenetic evolution and paleobiogeography of turtles from the dinosaur era. Author of “The Turtle’s Path” (NHK Publishing), “New Theories of Dinosaur Studies” (Kanzei), and the paper “Oldest known sea turtle” (Nature).

1 Popular Dinosaur Stories We Currently Understand
(Dinosaurs are “birds that don’t fly” / There are “carnivorous dinosaurs” but no “herbivorous dinosaurs” / Tyrannosaurus only hunted when young, etc.)

2 Dinosaur Stories That Overturn Common Knowledge
(Those who invested more in “fashion” were more popular / They were originally like birds—so why did they become like reptiles? / Was Archaeopteryx not the oldest bird?, etc.)

3 The Ever-Evolving Story of Dinosaur Research
(The birth of “dinosaurs” / Discovery and error in continuous excavation competition / The Dinosaur Renaissance, etc.)