This Work Offers an Introduction to the Application of Continuous Symmetries and Their Lie Algebras to Ordinary and Partial Differential Equations. It Should Be Suitable for Students and Research Workers Whose Main Interest Lies in Finding Solutions to Differential Equations. It Therefore Caters for Readers Primarily Interested in Applied Mathematics and Physics Rather Than Pure Mathematics. the Book Provides an Application-Orientated Text That is Self-Contained. Worked Examples Have Been Included to Help Readers Working Independently of a Teacher.