Introduction
摘要
This is an Introduction to the book Essays in Geometry, a collection of articles dedicated to Valentin Poénaru. The Introduction contains an overview of the whole book. It gives an idea of the content of each chapter and at the same time of the spectrum of subjects of interest of Poénaru. The topics discussed include topology, geometry, combinatorial group theory, history and philosophy of mathematics, mathematical physics. Several chapters are of autobiographical nature, written by Poénaru himself.