  The experimental status of measurements of the top quark mass is reviewed.
After an introduction to the definition of the top quark mass and the
production and decay of top quarks, an in-depth comparison of the analysis
techniques used in top quark mass measurements is presented, and the systematic
uncertainties on the top quark mass are discussed in detail. This allows the
reader to understand the experimental issues in the measurements, their
limitations, and potential future improvements, and to comprehend the inputs to
and formation of the current world average value of the top quark mass. Its
interpretation within the frameworks of the Standard Model and of models beyond
it are presented. Finally, future prospects for measurements of the top quark
mass and their impact on our understanding of particle physics are outlined.
