The combination of mechanical properties (strength, toughness, and crack arrestability) and weldability that is required of steel pipelines has led to the pipeline steel grades that are used today. The only way to control the mechanical properties of these grades is by controlling microstructure and crystallographic texture of the steel plates. In this chapter, descriptions are provided of the microstructure and texture in the most commonly used pipeline steel grades. The composition ranges of these grades are summarized, together with a brief discussion of segregation effects. After a short historical review, the general principles of microstructure and texture formation during the thermomechanically controlled processing of plate and sheet are discussed. These are illustrated with examples taken from the literature and the authors' research. Special attention is paid to texture formation, methods of texture control, and the influence of texture on mechanical properties, anisotropy, and fracture behavior of these microalloyed steels.