This book is entirely devoted to the area of visibility algorithms in computational geometry and covers basic algorithms for visibility problems in two dimensions. It is intended primarily for graduate students and researchers in the field of computational geometry. It will also be useful as a reference/text for researchers working in algorithms, robotics, graphics and geometric graph theory.

The area of visibility algorithms started as a sub-area of computational geometry in the late 1970s. Many researchers have contributed significantly to this area in the last three decades and helped this area to mature considerably. The time has come to document the important algorithms in this area in a text book. Although some of the existing books in computational geometry have covered a few visibility algorithms, this book provides detailed algorithms for several important visibility problems. Hence, this book should not be viewed as another book on computational geometry but complementary to the existing books.

In some published papers, visibility algorithms are presented first and then the correctness arguments are given, based on geometric properties. While presenting an algorithm in this book, the geometric properties are first established through lemmas and theorems, and then the algorithm is derived from them. My experience indicates that this style of presentation generally helps a reader in getting a better grasp of the fundamentals of the algorithms.