The Manthanabhairavatantra is about 24,000 verses long and is divided into three sections (khanda). The one edited and translated here is the Kumarikakhanda. Along with the Kubjikamata, the Manthanabhairavatantra is the most important and extensive Tantra dedicated to the worship of the goddess Kubjika. Although originally an Indian goddess, Kubjika is almost exclusively worshipped in the Kathmandu Valley, where her cult has been kept scrupulously secret by Newar initiates for centuries. Almost all the manuscripts of her Tantras and related literature have been found there. Kubjika is a powerful development of Malini, the principal goddess of the Trika Tantras and Kali of the Kashmiri Krama tradition. Her cult belongs to a chain of early Kaula systems that culminate with that of the goddess Tripura and so sheds considerable light on them. Kubjika’s unique historical importance is mirrored in the extraordinary richness of the inner, spiritual dimensions of her cult. These are explored in detail in the introduction to the edition and translation of the text with extensive references from mostly unpublished Kubjika Tantras and those of related schools. The work took close to two decades to produce. In this time numerous working editions of unpublished Tantras and related texts were prepared by the author with the help of a team of five trained assistants.