Nishmat Chayyim is a 17th-century work on the immortality of the soul by Menasseh ben Israel. In the work’s introduction, ben Israel describes a visit at dawn from a heavenly angel who commanded him to write the book and promised that he would guide ben Israel in the writing process. The book’s four sections address the journey of a soul from birth to its departure from the body, proofs for the concept of the soul’s reincarnation (known as “gilgul”), and an analysis of the existence of spirits and demons, utilizing Kabbalah.