Previous compilations of ( n,γ) cross sections of relevance for neutron capture nucleosynthesis in the big bang and in the slow neutron capture process ( s process) have been updated to encompass information available up to December 1998; data references include work in process then and published subsequently. The experimental results for nuclei between H and Bi were critically surveyed, renormalized to selected standard cross sections, and condensed into a set of recommended Maxwellian averaged cross sections for a thermal energy of kT=30 keV. Recent statistical model calculations of the capture cross sections made with the code NON-SMOKER are listed for comparison; these calculated cross sections are adopted in those cases where experimental information is still missing, e.g., for the majority of radioactive nuclei defining the s-process branchings. Maxwellian averages, normalized to our recommended 30 keV averages, were determined for a range of thermal energies between kT=5 and 100 keV. We have also included the calculated stellar enhancement factors due to thermally populated nuclear states as a function of temperature.