While the Bhagavad Gītā is an acknowledged treasure of world spiritual literature, few people know a parallel text, the Īśvara Gītā. This lesser-known work is also dedicated to a god, but in this case it is Śiva, rather than Kṛṣṇa, who is depicted as the omniscient creator of the world. Andrew J. Nicholson's Lord Śiva's Song makes this text available in English in an accessible new translation. A work of both poetry and philosophy, the Īśvara Gītā builds on the insights of Patanjali's Yoga Sūtra and foreshadows later developments in tantric yoga. It deals with the pluralistic religious environment of early medieval India through an exploration of the relationship between the gods Śiva and Viṣṇu. The work condemns sectarianism and violence and provides a strategy for accommodating conflicting religious claims in its own day and in our own.