The provided text is the introduction and preface of the book "Introduction to Mechanics and Symmetry" by Jerrold E. Marsden and Tudor S. Ratiu, published as part of the "Texts in Applied Mathematics" series by Springer Science+Business Media, LLC. The book is a comprehensive exposition of classical mechanical systems, emphasizing the geometric and analytical aspects of mechanics. It covers a wide range of topics, including Lagrangian and Hamiltonian formalisms, Lie-Poisson brackets, Poisson manifolds, momentum maps, infinite-dimensional systems, and applications to various physical systems such as rigid bodies, fluids, and plasma physics. The authors aim to provide a foundation for further study in mechanics and symmetry, with a focus on concrete applications and modern techniques. The book includes 54 illustrations and is intended for advanced undergraduate and beginning graduate students in science and engineering. The second edition features a solutions manual and additional internet supplements, enhancing the learning experience.The provided text is the introduction and preface of the book "Introduction to Mechanics and Symmetry" by Jerrold E. Marsden and Tudor S. Ratiu, published as part of the "Texts in Applied Mathematics" series by Springer Science+Business Media, LLC. The book is a comprehensive exposition of classical mechanical systems, emphasizing the geometric and analytical aspects of mechanics. It covers a wide range of topics, including Lagrangian and Hamiltonian formalisms, Lie-Poisson brackets, Poisson manifolds, momentum maps, infinite-dimensional systems, and applications to various physical systems such as rigid bodies, fluids, and plasma physics. The authors aim to provide a foundation for further study in mechanics and symmetry, with a focus on concrete applications and modern techniques. The book includes 54 illustrations and is intended for advanced undergraduate and beginning graduate students in science and engineering. The second edition features a solutions manual and additional internet supplements, enhancing the learning experience.