Can you contrast the 'knowledge texts' with the 'Guru biography texts' as they are presented in the preface?

The preface differentiates between two categories of spiritual literature. The first, referred to as 'knowledge texts,' are described as being sources of purely worldly and spiritual knowledge. The second category is 'Guru biography texts.' Chapter 0 clarifies that while both can be forms of Guru service, a biography has a more specific function. It is a true and reliable account of a Guru's entire existence, including their incarnation, life stages, miracles ('Leelas'), and major works. So, while a knowledge text might discuss philosophy, a biography focuses on the life of the teacher who embodies that philosophy.