This document provides an introduction to bioequivalence studies, including definitions of key terms, the need for and importance of bioequivalence studies, criteria for establishing a bioequivalence requirement, types of bioequivalence studies, design of bioequivalence studies, evaluation of bioequivalence study results, and clinical significance. It discusses in vivo and in vitro bioequivalence study types and designs, including factors such as single dose, multiple dose, fasting, food effect, and crossover designs. Statistical evaluation methods including ANOVA, confidence intervals, and bioequivalence limits of 80-125% are also summarized.