The paper reviews basic theoretical studies of laminar film condensation since Nusselt (1916). Particular attention is given to those investigations in which the relative importance of the additional complicating factors is revealed and where approximate heat-transfer formulae are provided. For natural convection condensation on vertical plates and horizontal tubes, detailed solutions show that the simple Nusselt results (Eqs. (16) and) are surprisingly accurate over a wide range of conditions. Effects of inertia and convection in the condensate film and vapour shear at the condensate surface are generally of minor importance. Relatively simple, accurate, equations, which take account of these factors, are, however, available (Eqs. (30) and (32)). For forced convection condensation, detailed solutions for horizontal plates indicate that inertia and convection are generally unimportant for the normal practical ranges of the variables. A relatively simple result (Eq. (63)), equivalent to the Nusselt equation for natural convection, gives the heat transfer for this case with good accuracy. An interpolation formula (Eqs. (64) and (67)), which satisfies equations (16) and (63) for the natural and forced convection dominated extremes, gives accurate results for condensation in downflow over a vertical plate. For forced convection condensation on a horizontal tube, vapour boundary layer separation and condensate film instability resulting from opposing effects of vapour shear stress and pressure gradient over the downstream half of the tube, present significant difficulties. Approximate equations which either neglect these effects or make conservative allowances are available.