  Galaxy redshift surveys are one of the key probes in modern cosmology. In the
data analysis of galaxy surveys, the precision of the statistical measurement
is primarily limited by the cosmic variance on large scales. Fortunately, this
limitation can in principle be evaded by observing multiple types of biased
tracers. In this brief review, we present the idea of the multi-tracer method,
outline key steps in the data analysis, and show several worked examples based
on the GAMA, BOSS and eBOSS galaxy surveys.
