Theory and modelling with direct numerical simulation and experimental observations are indispensable in the understanding of the evolution of nature, in this case the theory and modelling of plasma and fluid turbulence. Plasma and Fluid Turbulence: Theory and Modelling explains modelling methodologies in depth with regard to turbulence phenomena and turbulent transport both in fluids and plasmas. Special attention is paid to structural formation and transitions. In this detailed book, the authors examine the underlying ideas describing turbulence, turbulent transport, and structural transitions in plasmas and fluids. By comparing and contrasting turbulence in fluids and plasmas, they demonstrate the basic physical principles common to fluids and plasmas while also highlighting particular differences. The book also discusses the application of these ideas to neutral fluids. Part I presents a general introduction to turbulence and structural formation in fluids and plasmas, and Part II explains methodologies for fluid turbulence. In Part III, the authors describe the subjects in magnetohydrodynamics, in particular, dynamo problems. The final section, Part IV, considers plasma turbulence and transport.