The flows of non-Newtonian fluids are important in chemical engineering, lubrication and tribology, polymer devolatisation, bubble columns etc. Analysis of the magnetohydrodynamic (MHD) effect on the flows of such fluids has shown an increasing amount of attention in recent times. Such interest stems because of the occurrence of these liquids in industrial processes. The constitutive relationships between the stress and rate of strain quite complicated for non-Newtonian fluids. Consequently, the mathematical analysis for the flows of such fluids involves equations with more nonlinear terms.Therefore, finding accurate solutions to equations of non-Newtonian fluids is not an easy task. The boundary layer flows due to a stretching sheet are of great interest in many engineering applications. Some of the practical examples of such problems are glass fiber and paper production, continuous casting, hot rolling, cooling of electronic chips etc. There has been a renewed interest in developing analytical and numerical solutions for nonlinear problems of stretching / shrinking flows. Having these facts in mind this book provides analytical and numerical solutions for non-linear fluids.