In 25 years since the first edition of Experiencing Geometry this book has influenced many people how they think about geometry and mathematics in general. The unique spirit of David Henderson's method of learning geometry is kept alive in this 4th edition of the book. The format of the book is the same as it was in the third edition (2005). New in this book is an expanded chapter on historical strands of geometry, updates throughout the book with new results and references, particularly Chapter 24 The Shape of Space. There is a significantly expanded Appendix on how to make different models and also suggestions for projects in geometry. This new edition has much more visual material than previous editions. Experiencing Geometry: Euclidean and non-Euclidean with History can be used as a textbook for geometry class, but also it can be used as a self-study guide.