Coincidance: A Head Test is a book by Robert Anton Wilson

Robert Anton Wilson

Robert Anton Wilson , known to friends as "Bob", was an American author and polymath who became at various times a novelist, philosopher, psychologist, essayist, editor, playwright, poet, futurist, civil libertarian and self-described agnostic mystic...

, published in 1988. It consist of series of essays in four parts prefaced by a foreword from the author. It covers familiar Wilson territory such as the writings of James Joyce

James Joyce

James Augustine Aloysius Joyce was an Irish novelist and poet, considered to be one of the most influential writers in the modernist avant-garde of the early 20th century...

, Carl Jung

Carl Jung

Carl Gustav Jung was a Swiss psychiatrist and the founder of Analytical Psychology. Jung is considered the first modern psychiatrist to view the human psyche as "by nature religious" and make it the focus of exploration. Jung is one of the best known researchers in the field of dream analysis and...

, linguistics

Linguistics

Linguistics is the scientific study of human language. Linguistics can be broadly broken into three categories or subfields of study: language form, language meaning, and language in context....

 and coincidence

Coincidence

A coincidence is an event notable for its occurring in conjunction with other conditions, e.g. another event. As such, a coincidence occurs when something uncanny, accidental and unexpected happens under conditions named, but not under a defined relationship...

. As explained on the back cover the title is a deliberate misspelling suggesting the “mad dervish

Dervish

A Dervish or Darvesh is someone treading a Sufi Muslim ascetic path or "Tariqah", known for their extreme poverty and austerity, similar to mendicant friars in Christianity or Hindu/Buddhist/Jain sadhus.-Etymology:The Persian word darvīsh is of ancient origin and descends from a Proto-Iranian...

whirl of coincidence and synchronicity” to be found within.