The Kālacakra Tantra has three aspects, ‘outer’, ‘inner’, and ‘other’. The ‘outer’ is lore concerning the environment: astrology, history, eschatology; the ‘inner’ concerns the esoteric physiology of the ‘subtle body’; the ‘other’ consists of the ‘generation’ and ‘completion’ stages of yoga, and aims to purify the ‘outer’ and ‘inner’ aspects. Of these, the ‘generation’ (utpattikrama) involves the visualization of the 722 deities of the Kālacakra maṇḍala, which has at its centre the Ādi buddha in the form of the sexual union (yab-yum) of Kālacakra and Vishvamātā. The ‘completion’ (sampannakrama) stage involves the manipulation of one's subtle energies to produce a consciousness with the capacity for enlightenment. Kālacakra is a member of the Anuttara (unsurpassed) class of tantras, and as such offers buddhahood through its mastery.
"Kālacakra." The Concise Oxford Dictionary of World Religions. . Encyclopedia.com. (August 14, 2018). http://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/kalacakra
"Kālacakra." The Concise Oxford Dictionary of World Religions. . Retrieved August 14, 2018 from Encyclopedia.com: http://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/kalacakra