  We present an estimate of the global budget of baryons in all states, with
conservative estimates of the uncertainties, based on all relevant information
we have been able to marshal. Most of the baryons today are still in the form
of ionized gas, which contributes a mean density uncertain by a factor of about
four. Stars and their remnants are a relatively minor component, comprising for
our best-guess plasma density only about 17% of the baryons, while populations
contributing most of the blue starlight comprise less than 5%. The formation of
galaxies and of stars within them appears to be a globally inefficient process.
The sum over our budget, expressed as a fraction of the critical Einstein-de
Sitter density, is in the range $0.007\lsim\Omega_B\lsim 0.041$, with a best
guess $\Omega_B\sim 0.021$ (at Hubble constant 70 km/s/Mpc). The central value
agrees with the prediction from the theory of light element production and with
measures of the density of intergalactic plasma at redshift $z\sim 3$. This
apparent concordance suggests we may be close to a complete survey of the major
states of the baryons.
