Local coefficients of heat transfer from a 12.3-in. length of 0.252-in. tubing to steam flowing upward in a vertical annulus were measured for pressures from 115 to 3500 psia, for temperatures from 430 to 1000 F, and for temperature differences from 100 to 620 F. All results are correlated in Fig. 8 in terms of the local Nusselt number, the Reynolds number, the Prandtl number, and the geometrical ratio L/Dc with the physical properties evaluated at the film temperature. An improved correlation, employing new data on thermal conductivity, is presented in Fig. 10 of the Addendum.