{Comparing \TeX{} engines and formats} {Max Chernoff} {Initially, \TeX{} was a single engine and a single format. However, over the past 40 years, the number of engines and formats has significantly grown, meaning that there are multiple ways of implementing similar solutions depending on the \TeX{} variant used. In this talk, I'll introduce and compare each engine and format, focusing on both history and practical tips.}