Charles Marsh, in a long essay in which he responds to criticisms of Strange Glory (particularly those leveled by Ferdinand Schlingensiepen), with some ruminations (selectively chosen on my part) on biography as a genre and his approach to his subject, Dietrich Bonhoeffer:

The biographer feasts upon the singularities of lived experience. […]

As Leon Edel writes, “Biography is a record, in words, of something that is as mercurial and as flowing, as compact of temperament and emotion, as the human spirit itself.” To which I would add that biography is memory of particular bodies committed to narrative. […]

My approach was to portray Bonhoeffer in his singular complexity, which is to say, his strange glory. […]

At the level of craft, telling a theological life should be no different than telling any other kind of life. Every good biographer maintains the desire to save a personality from the clutch of familiarity. The challenge is in determining how to enlist the tenets of belief in service to story. The infinite does not appear in the dramatis personae; instead, theologians enumerate transcendence under the terms of specific doctrinal commitments. It may be said of the theological biography that it tells a life out of a “higher satisfaction” (to borrow a phrase from Bonhoeffer), but this should not be taken as a method or dogma. The theological biographer writes with the hope of rendering the character’s faith as vivid and credible elements of the story. Otherwise I feel rather agnostic toward the idea of a theological biography. […]

Biography is built on historical reality, of course, but its purpose is finding the truth in the life. This does not mean finding the authentic or essential self but the patterns and manners, “the doubts and vulnerabilities, ambitions and private satisfactions that are hidden within the social personality.” […]

Biography came to me as a quest to capture what Hermione Lee describes as “the ‘vital spark’ of the human subject.” To readers familiar with Bonhoeffer’s story, I wanted to create a sense of discovery so that they could encounter him as if for the first time, encounter him in his strange glory. For those unfamiliar with Bonhoeffer, I wanted to do all the things biographers hope for when they write well: approximate in narrative nonfiction “the presence of recognizable, approachable life . . . to catch the special gleam of character.”