Few words are as widely misconceived as the word "faith." Faith is often set in stark opposition to reason, considered antithetical to scientific thought, and heavily identified with religion. Donald Crosby's revealing book provides a more complex picture, discussing faith and its connection to the whole of human life and human knowledge. Crosby writes about that existential faith that underlies, shapes, and supports a person's life and its sense of purpose and direction. Such faith does not make a person religious and being secular does not mean one rejects all forms of faith. Throughout the book Crosby makes the case that faith is fundamentally involved in all processes of reasoning and that reason is an essential part of all dependable forms of faith.

Crosby elaborates the major components of faith and goes on to look at the mutually dependent relationships between faith and knowledge, faith and scientific knowledge, and faith and morality. The work's final chapters examine crises of faith among several noted thinkers as well as the author's own journey of faith from plans for the ministry to pastor to secular philosopher and religious naturalist.