This document discusses the uses of the word "by" in English. It can be used to indicate who is responsible for an activity or how something is done. Examples are given such as "This song was composed by Schubert" and "The seeds were sown by farmers." It also compares the uses of "by", "with", "on", "in", and "beside." For instance, "by" is used to indicate means or method, while "with" refers to the instrument used. The document provides rules and examples for when to use each of these words depending on the context.