The Book on Adler (subtitle: The Religious Confusion of the Present Age, Illustrated by Magister Adler as a Phenomenon, A Mimical Monograph) is a work by the Danish philosopher Søren Kierkegaard, written during his second authorship, and was published posthumously in 1872.

The work is partly about pastor Adolph Peter Adler who claimed to have received a revelation.

After some questionable acts, Adler was subsequently dismissed from his pastor duties.

The rest of the work focuses on the concept of authority and how it relates to Adler's situation.

If we want to get an idea of what qualitative dialectics has to say when turned upon a very definite question, we ought to study the book about Adler".