  Although cluster dwarf galaxies are often neglected due to their faintness,
recent observations demonstrate that they are critical for understanding the
physical processes behind galaxy and cluster formation. Dwarfs are the most
common galaxy type and are particularly abundant in clusters. Recent
observational results suggest that dwarfs in dense environments do not all form
early in the universe, as expected from hierarchical structure formation
models. Many of these systems appear to be younger and more metal rich than
dwarfs in lower density areas, suggesting they are possibly created by a tidal
process. Several general galaxy cluster observations, including steep
luminosity functions and the origin of intracluster light, are natural outcomes
of these processes.
