The current state of knowledge is surveyed here on the dynamics and gravitational properties of cosmic strings treated in the idealized classical approximation as line singularities described by the Nambu- Goto action. The aim of the book is to provide a standard reference to all work that has been published since the mid-1970s and to link this work together in a single conceptual framework and a single notational formalism. A working knowledge of basic general relativity is assumed. The book is for researchers and postgraduate students in mathematics, theoretical physics, and astronomy. Anderson is affiliated with the Department of Mathematics at University Brunei, Darussalam.