Even though many characteristics of the quiescent crystallisation process of polymers have been deeply investigated in the long run, some subjects are still open. Indeed, the theory of nucleation and growth, originally developed for metals and low molecular weight materials, have been extended to polymers without taking into account all the characteristics of macromolecules that can induce a crystallisation behaviour different from that of atoms or small molecules. This paper, within the framework of nucleation and growth, reviews the main aspects of the crystallisation process of polymers and discusses its influence on the microstructure, also in comparison with metallic and ceramic materials. Additional factors, often neglected, affecting the crystallisation process have been also identified. In particular, consideration is given to heat flow from solid to melt during polymer crystallisation that can provide an explanation for modified spherulitic morphologies found in fibre based composite materials and blends. Moreover, the circumstances under which thermal gradients within polymer samples may play a dominant role in crystallisation are underlined. Finally, several examples of polymer textures, that could have been originated by heat transfer anisotropy inside samples, are shown.