  The cosmological evolution of neutral hydrogen is an efficient way of tracing
structure formation with redshift. It indicates the rate of evolution of gas
into stars and hence the gas consumption and rate star formation history of the
Universe. In measuring HI, quasar absorbers have proven to be an ideal tool and
we use observations from a recent survey for high-redshift quasar absorption
systems together with data gathered from the literature to measure the
cosmological comoving mass density of neutral gas. This paper assumes
Omega_M=0.3, Omega_lambda=0.7 and h=0.65.
