Dr. Pasedach, Peter: Śivasaṃhitā, critical edition
The Śivasaṃhitā, of unknown authorship, is one of the important texts of Haṭhayoga. It deals with a wide variety of subjects, such as advaita philosophy, the yogic body, the guru and disciple, prāṇāyāma and mudrās. The term Haṭhayoga is used only in its fifth and last chapter, which might have at an earlier point been a separate text. In it, a Rājādhirājayoga is taught. The Śivasaṃhitā calls itself a Tantra, and shows influence of the Śrīvidyā tantric tradition, subscribing to an advaita position. It is aimed at householders. It still awaits to be fully critically edited.
Peter Pasedach has commenced a digital critical edition. https://muk.li/upama/sivasamhita