Functional Equations have a significant place in Mathematical Olympiads and have been a mainstay in many competitions, including the IMO. This book aims to strengthen the readers’ foundation in functional equations with in-depth discussions on various concepts and techniques.This book will take you on the beautiful journey of the functional equation. This book contains numerous examples with their lucid explanations and motivation for key steps. The most interesting part of the book is that it teaches the reader how to appropriately think or approach a problem accurately and solve them efficiently and thereby clearing the tough concepts to the readers.