For over a thousand years, the Śūraṅgama Sūtra — the “Sutra of the Indestructible” — has been held in great esteem in the Mahāyāna Buddhist countries of East and Southeast Asia. In China the Sutra has generally been considered as important and has been as popular as the Lotus Sūtra, the Avataṁsaka Sūtra, the Mahāyāna Mahāparinirvāṇa Sūtra, the Heart Sūtra, and the Diamond Sūtra. The appeal of the Śūraṅgama Sūtra lies in the broad scope of its teachings and in the depth and clarity of its pre-scriptions for contemplative practice. Because of its wealth of theoretical and practical instruction in the spiritual life, it was often the first major text to be studied by newly ordained monks, particularly in the Chan school...
More specifically, the Śūraṅgama Sūtra has traditionally been regarded as a complete and practical manual for spiritual practice that will eventually lead to enlightenment. It gives instruction in the correct understanding of the Buddha-nature, which is the potential within all beings for becoming a Buddha. The Sutra explains how and why this true nature is hidden within our ordinary experience of ourselves and of the world, and it shows how we can uncover this nature and recognize that it is our own true mind. The Sutra also explains that personal integrity and purity of conduct are essential prerequisites for spiritual awakening.
From the Introduction.