Redshift surveys of galaxies have been for the past two decades one of the most useful tools available for cosmological studies. Since the pioneering work of Gregory and Thompson (1978) and Sandage (1978), among others, progress has been enormous, with the pace being dictated primarily by advances in technology. Arguably one of the most significant early milestones in the field was the start of the Center for Astrophysics Redshift Survey in 1978, one of the first surveys to replace photographic plates by significantly more efficient detectors, making large scale surveys possible. Similar systems soon became available at several observatories and the number of surveys, using different samples and observing strategies, flourished in the 80s. New developments in the 90s further increased the data gathering power of surveys making possible to probe much larger volumes. Combined these surveys have provided a wealth of information regarding the properties of galaxies, systems of galaxies and the nature of large-scale structure (LSS) as traced by galaxies.
Despite the enormous effort a number of outstanding cosmological questions remain unanswered pointing out the need for even larger surveys. Projects like the Anglo-Australian 2dF and the Sloan Digital Sky Survey (SDSS) represent the beginning of a new era in the field and promise to provide clear answers to these questions. Another milestone are the ongoing (Steidel, this proceeding) and the planned redshift surveys of the high-z Universe on Keck and VLT which will provide a better understanding of the nature of distant galaxies, their clustering properties and insight into early galaxy and structure evolution.
Over the years the goal of most galaxy redshift surveys have remained essentially the same, namely to obtain redshifts for complete samples over a sufficiently large volume to: 1) study the nature of large scale structure; 2) measure the cosmological density parameter from dynamical measurements on small and large scales; 3) compare observed galaxy distribution to predictions based on N-body simulations in an attempt to discriminate among competing theoretical models; 4) compare the galaxy distribution to the mass distribution as recovered, for instance, from the peculiar velocity field of galaxies; and 5) study galaxy biasing on small and large scales. Even though galaxy redshift surveys alone provide only limited information about the underlying mass fluctuations, they will continue to be essential for probing galaxy biasing and evolution models, complementing the information from probes of the mass distribution such as cosmic flows, gravitational lensing and cosmic microwave background radiation.
The literature on large-scale structure has grown tremendously and a comprehensive review on the subject would be well beyond the scope of this presentation and can be found elsewhere (e.g., Giovanelli & Haynes 1991, Strauss & Willick 1995). Instead, the aim of this review is to illustrate how our picture of the Universe has evolved over the past two decades with the completion of various surveys targeting different redshift intervals. Also reviewed are the results of quantitative analyses carried out with redshift data to describe galaxy clustering as well as the properties of the galaxy population as a whole.