This book focuses on the computational and theoretical approaches to the coupling of fluid mechanics and solids mechanics. In particular, nonlinear dynamical systems are introduced to the handling of complex fluid-solid interaction systems, For the past few decades, many terminologies have been introduced to this field, namely, flow-induced vibration, aeroelasticity, hydroelasticity, fluid-structure interaction, fluid-solid interaction, and more recently multi-physics problems. Moreover, engineering applications are distributed within different disciplines, such as nuclear, civil, aerospace, ocean, chemical, electrical, and mechanical engineering. Regrettably, while each particular subject is by itself very extensive, it has been difficult for a single book to cover in a reasonable depth and in the mean time to connect various topics. In light of the current multidisciplinary research need in nanotechnology and bioengineering, there is an urgent need for books to provide such a linkage and to lay a foundation for more specialized fields.