  In this review, we present a brief description of observational efforts to
understand the Galactic thick disk and its relation to the other Galactic
components. This review primarily focused on elemental abundance patterns of
the thick disk population to pin down the process or processes that were
responsible for its existence and evolution. Kinematic and chemical properties
of disk stars establish that the thick disk is a distinct component in the
Milky Way. The chemical enrichment and star formation histories hold clues to
the bigger picture of understanding the Galaxy formation.
