This book describes the energy method, a powerful technique for deriving nonlinear stability estimates in thermal convection contexts. It includes a very readable introduction to the subject (Chapters 2-4), which begins at an elementary level and explains the energy method in great detail, and also covers the current topic of convection in porous media, introducing simple models and then showing how useful stability results can be derived. In addition to the basic explanation, many examples from diverse areas of fluid mechanics are described. The book also mentions new areas where the methods are being used, for example, mathematical biology and finance. Several of the results given are published here for the first time.

This book is a substantially revised edition of the author's earlier volume of the same title. It presents convection studies in a variety of fluid and porous media contexts, and will be accessible to a wide audience of applied mathematicians, physicists, and engineers.

1 Introduction.- 2 Illustration of the energy method.- 3 The Navier-Stokes equations and the Bénard problem.- 4 Symmetry, competing effects, and coupling parameters.- 5 Convection problems in a half space.- 6 Generalized energies and the Lyapunov method.- 7 Geophysical problems.- 8 Surface tension driven convection.- 9 Convection in generalized fluids.- 10 Time dependent basic states.- 11 Electrohydrodynamic and magnetohydrodynamic convection.- 12 Ferrohydrodynamic convection.- 13 Reacting viscous fluids.- 14 Multi-component convection diffusion.- 15 Convection in a compressible fluid.- 16 Temperature dependent fluid properties.- 17 Penetrative convection.- 18 Nonlinear stability in ocean circulation models.- 19 Numerical solution of eigenvalue problems.- A Useful inequalities.- A.1 The Poincaré inequality.- A.2 The Wirtinger inequality.- A.3 The Sobolev inequality.- A.4 An inequality for the supremum of a function.- A.7 A two-dimensional surface inequality.- A.8 Inequality (A.20) is false in three-dimensions.- References.