  The heaviest known elementary particle, the top quark, was discovered in 1995
by the CDF and D0 collaborations at the Tevatron proton-antiproton collider at
Fermilab. Since its discovery, a large program was set in motion by the CDF and
D0 collaborations to characterize the production and decay properties of top
quarks, and investigate their potential for searches of new phenomena beyond
the standard model. During the past 20 years, new methods were developed and
implemented to improve the measurements and searches for new physics in the
top-quark sector. This article reviews the achievements and results obtained
through studies of the top quark at the Tevatron.
