The book "Non-Newtonian Fluid Mechanics and Complex Flows" offers a comprehensive analysis of the mathematical challenges that arise in modeling non-Newtonian fluids. It addresses the differences in flow properties between non-Newtonian and Newtonian fluids and highlights the relevance of this topic in various biological and industrial applications. The authors present a variety of contemporary problems along with their mathematical and physical modeling. This work is particularly valuable for professionals and students engaged in the dynamics of complex flows and their applications in engineering and natural sciences. The topics covered are of great importance for understanding fluids that exhibit an internal structure, such as biological fluids, polymer solutions, and other relevant substances.