I Will Bear Witness was originally written by Victor Klemperer in German and later translated into English by Martin Chalmers. The book is a diary, and it details Klemperer's experiences living as a Jew from 1933 to 1941 in Germany.

Klemperer was born in Germany in 1881. He was born to Jewish parents but was baptized into the Protestant faith at a young age. At the time of the writing of this diary, Klemperer had been granted a dispensation due to his military service in the German army during World War I; this—and the fact that he was married to an Aryan woman—helped protect him from some of the more egregious violence directed at Jewish people during this time. However, Klemperer and his wife Eva certainly suffered many indignities at the hands of the Nazis, including having their home searched and Klemperer being banned from using the library, driving a car, or riding the ferry.

Klemperer—as the author of the diary—is the main "character" of the story. He mentions Eva and correspondence with his brother Georg, but we mostly read about Klemperer's daily interactions with secondary characters.