  Dark matter in galaxies, its abundance, and its distribution remain a subject
of long-standing discussion, especially in view of the fact that neither dark
matter particles nor dark matter bodies have yet been found. Experts' opinions
range from a very large number of completely dark galaxies exist to nonbaryonic
dark matter does not exist at all in any significant amounts. We discuss
astronomical evidence for the existence of dark matter and its connection with
visible matter and examine attempts to estimate its mass and distribution in
galaxies from photometry, dynamics, gravitational lensing, and other
observations (the cosmological aspects of the existence of dark matter are not
considered in this review). In our view, the presence of dark matter in and
around galaxies is a well-established fact. We conclude with an overview of
mechanisms by which a dark halo can influence intragalactic processes.
