Based on the preface, what different classifications of Guru biographies can be identified, and which works fit into them?

The preface in Chapter 0 implicitly categorizes Guru biographies in several ways. There are the major, detailed works like those by Shri Saraswati Gangadhar and Shri Annasaheb Dabholkar. A second category is the excellent but 'very short' biography, exemplified by the two written by Shri Dasganu Maharaj. A third classification is the self-written biography, such as the one by Shri Samarth Sadguru Vasudevanand Saraswati Maharaj, which is distinguished from those written by devotees. Finally, the text identifies older, shorter versions of works, like the 'Laghu Guru Charitra,' which is distinct from the more famous 'Brihad Guru Charitra.'