This document discusses the use of the apostrophe s ('s) to indicate possession in English. It provides examples of how the apostrophe s is used to show possession of singular and plural nouns, irregular plurals, and possessors with multiple nouns. It also discusses how the apostrophe s is used with proper nouns, archaic terms, and whole sentences, as well as with somebody, somebody, institutions, countries, cities, measures of time, distance, and weight. The document notes some idiomatic uses and instances where the indication of possession can be omitted.