How does the preface distinguish between writing the biography of a worldly figure and writing one for a saint?

The preface in Chapter 0 draws a clear distinction between these two forms of service. Writing biographies of worldly 'Gurus'—such as politicians, warriors, or writers—is defined as a worldly service whose importance is limited by time and space and does not yield spiritual fruits. In contrast, writing the biographies of saints is presented as a form of Guru service that yields spiritual benefits. However, the preface clarifies that even this is partial compared to the ultimate service of writing about one's own Sadguru, which is described as the most certain path to the ultimate spiritual goal.