An unknown author writes an unlikely book and inadvertently sparks an improbable global movement.

The manuscript was written longhand on a yellow pad in a small Oregon town by a Quaker pastor describing twelve ancient Christian disciplines (the very definition of the term "unlikely"). But publishers at Harper & Row saw something special in what Richard Foster had written and took a risk.

The movement kindled by the book developed slowly, almost imperceptibly. But once it caught hold, it exploded into flame.

Celebration of Discipline was conceived during a period in history that Charles Dickens might describe as being the best of times and the worst of times. From its inception, American culture had been linked to Christian faith and values. We were "one nation under God, indivisible, with liberty and justice for all." The 1950s and early '60s saw the peak years of American churchgoing, when 70 percent of citizens attended church. But as the decade of the '60s stretched on, values and perspectives that had long been accepted as foundational to American faith and life began to come into question.

When Celebration of Discipline spotlighted the superficiality that had come to characterize Christianity, it ignited the spiritual formation movement by prescribing the ancient spiritual practices as the necessary corrective. Michael Maudlin, religion publisher at HarperCollins, acknowledges, "People do not remember how Christians thought about spiritual formation in Christ before Celebration of Discipline was published. Most everybody now thinks it is natural for evangelicals to practice spiritual Disciplines. But it was not always so. Celebration of Discipline serves as a wonderful window into how a book can change a subculture."

This is the story of that book.