This paper presents provides a comprehensive survey of dwarf galaxies, which represent the most numerous and diverse systems in the Universe. We discuss their definitions and morphological classifications, emphasizing the unique properties that distinguish them from globular clusters and giant galaxies. Special attention is given to their formation and evolutionary processes in the framework of hierarchical structure formation and ΛCDM cosmology, including the role of environmental mechanisms and stellar feedback. Star formation histories are explored based on observations and simulations, highlighting both bursty and extended activity across different dwarf types. We further examine the crucial role of dark matter in shaping the dynamics and structure of dwarf galaxies, as well as the core–cusp and missing satellites problems. Finally, we summarize insights from numerical simulations and theoretical models, which provide a bridge between observations and cosmological predictions. This synthesis demonstrates that dwarf galaxies remain essential laboratories for testing galaxy formation theories and probing the nature of dark matter.