This book provides a comprehensive overview of the current progress in fiber-reinforced plastics (FRP), covering manufacturing, mechanical behavior, and resistance performance. It includes the elastic and damage behavior of unidirectional FRP, and highlights the improvements achieved by adding multiwall carbon nanotubes. The material resistance is assessed through fatigue response, local behavior, local properties, and failure mechanisms, including crack density and microcrack propagation behavior. The book also explores the degradation of macroscopic mechanical properties such as elastic modulus and compressive strength versus plastic strains. Additionally, it focuses on the progress made in out-of-plane composite characterization and modeling response for simulations of critical mechanical parts currently used in different industries, thanks to advances in manufacturing techniques that allow for the production of increasingly complex and thicker geometries.