We present a theoretical formalism to predict two-point clustering statisti
cs (the power spectrum and the two-point correlation function), which simul
taneously takes account of the linear velocity distortion, the nonlinear ve
locity distortion (finger-of-god), the cosmological redshift-space distorti
on, and the light-cone effect. To demonstrate the importance of these effec
ts in exploring the clustering of objects at high redshifts, we show severa
l model predictions for magnitude-limited surveys of galaxies and quasars.
This methodology provides a quantitative tool to test various theoretical m
odels against the upcoming precision data on clustering in the universe.