Circle is as the compromising solution to substitute versatile complex geometric object had been widely applied in the fields of robotics, computational geometry, and CAD/CAM. This book is devoted in developing efficient methods for constructing the minimum traversal path of n circles in 2D plane. With the algorithms provided in this book, when distributing n mutually exclusive circles in a 2D plane, the shortest path can be constructed very fast which traverses from a given starting point to all of the n circles and finished at the ending point such that the Euclidean distance of the path is a minimum. The algorithms are applicable for computer systems in real world applications. Professionals in the fields of computer science especially in computational geometry, circle packing, path planning, tool path planning in layered manufacturing, computer-aided design and manufacturing, optimization, or anyone who may be interested in light reflection (or refraction), geometry, and the balance of torques of mechanics may catch some inspirations from the book.