  In this paper we review the importance of the Lyman alpha forest as a probe
of structure formation in the universe. We first discuss the statistics used to
describe the Lyman alpha forest and the numerical techniques used to produce
simulated spectra of the forest from a given cosmological model. We then
discuss the physical picture of the absorbing structures that emerges from
these numerical simulations. Finally, we comment on how two of the statistics,
the slope of the column density distribution and the b parameter distribution,
may be used to constrain competing cosmologies.
