An Introduction to Jain Philosophy is primarily based on a compilation of extraordinary writings and transcripts of discourses by Ācārya Sushil Kumar, in addition to the author’s personal conversations with him, all of which eloquently describe the Jain philosophy. Ācārya Sushil Kumar (affectionately addressed as Gurujī by his followers) was a great Jain monk during the twentieth century. He was astoundingly knowledgeable and was unmatched as a Jain philosopher. With an unwavering belief in the teachings of Lord Mahāvīra, Gurujī lived a truly fulfilling life of a Jain mendicant. His deep and unblemished understanding of the doctrine was instrumental in enabling him to succinctly discern and articulate the intricacies of Jain teachings in easy-to-follow terms. Gurujī was a tremendous orator who captivated large audiences in his frequent sermons. Using the same acumen, he explained the doctrine in his writings and discourses while staying on the philosophical plane, avoiding ritualistic and sectarian aspects. With all these inimitable attributes, his work is uniquely qualified source of learning for all those who are hungry to study a doctrine that is so important and critically relevant for humanity today.
Learning from exalted individuals like Ācārya Sushil Kumar is edifying and transformative in very subtle ways, even by being in their proximity and observing them. The following link provides a brief biography of Gurujī.
Ācārya Sushil Kumar, from An Introduction to Jain Philosophy