What is the purpose of the invocations at the beginning of Shri Sai Satcharitra, and which deities are primarily invoked?

According to Chapter 1, the purpose of the auspicious invocations, known as Mangalacharan, is to ensure the obstacle-free completion of the task at hand and to obtain the grace of the desired deity. This traditional practice is adopted for attaining auspiciousness and fulfilling the author's goal of writing the book. The first chapter begins with salutations to several deities, but the primary focus is first on Lord Ganesha, the remover of obstacles. This is followed by invocations to Goddess Saraswati for the power of speech and literature, the divine trinity of Brahma, Vishnu, and Shankar, and finally, the family deity Narayana.