In recent years a number of authors have found solutions to the Einstein-Maxwell field equations for static gravitational fields with isotropic matter. These solutions may be utilized to model a charged relativistic star as they are matchable to the Reissner-Nordstrom exterior at the boundary. It is for this reason that many investigators use a variety of techniques to attain exact solutions. This book provides exact solutions to the isotropic Einstein-Maxwell system that model the interior of relativistic stars. The field equations are transformed to simpler forms; the integration of the system is reduced to solving the condition of pressure isotropy. New classes of solutions of linearly independent functions are obtained in terms of special and elementary functions for different spatial geometries. In addition, two exact analytical solutions describing the interior of a charged strange quark star are obtained by applying the MIT bag equation of state. This book is addressed to graduate students in Mathematics/Physics and to professional Mathematician/Physicist, with interest in exact interior solutions for charged fluid spheres.