The book by Dr. Daniel Kaplan and Professor Leon Glass “Understanding Nonlinear Dynamics” is intended for graduate students of universities majoring in biology, biochemistry and biophysics. The book serves as an accessible introduction to modern problems of nonlinear dynamics. It contains chapters on stability, multistability, cellular automata and active media, fractals, dimension, cycles and chaos. A separate chapter contains material on numerical analysis of time series, which is important for experimental studies of the dynamics of nonlinear systems. The book does not claim to be a strict mathematical description of the problems under consideration, assuming that students have appropriate training in the physical and mathematical disciplines of university programs. At the same time, the book contains a large number of interesting examples and problems of an applied nature, which is very important for stimulating independent work. The book is written in an interesting, accessible language and will be useful as a textbook on applied nonlinear dynamics for students studying life sciences.