This book is divided into three parts and includes new results, reviews, and recent developments of some special topics on Hydrodynamics, Dynamical Systems, Astrophysics, Quantum Mechanics, Relativity, and DNA evolution. The first part deals with Hydrodynamics including historical aspects, applications of recent theories to extend the Navier-Stokes regime, and new results on known methods for going beyond the Navier-Stokes equations. The second part is devoted to Dynamical Systems including new results on the problem of regularization of collisions and the Poincaré continuation method. The second part also contains reviews of several aspects of the theory of Dynamical Systems. The third part deals with microquasars and astrophysics, fundamental aspects of Quantum Mechanics, superluminal propagation, and DNA evolution.