A namtar is a spiritual biography or hagiography

Hagiography

Hagiography is the study of saints.From the Greek and , it refers literally to writings on the subject of such holy people, and specifically to the biographies of saints and ecclesiastical leaders. The term hagiology, the study of hagiography, is also current in English, though less common...

 in Tibetan Buddhism

Tibetan Buddhism

Tibetan Buddhism is the body of Buddhist religious doctrine and institutions characteristic of Tibet and certain regions of the Himalayas, including northern Nepal, Bhutan, and India . It is the state religion of Bhutan...

.

Namtar literally means 'complete liberation', since the texts tell the stories of yogis or Indo-Tibetan Mahasiddha

Mahasiddha

Mahasiddha is a term for one who cultivates those teachings that lead to becoming perfect. They are a type of eccentric yogini/yogi in both Sanatan Dharma and Vajrayana Dharma, given by Siddhartha. Mahasiddhi are those practitioners, or tantrikas who have gained sufficient understanding and are so...

 who attained complete enlightenment. Namtars do not focus on a literal chronology of events, but rather function as a kind of learning example that hits the high points of the sprititual life of a yogi.

In her book, Women of Wisdom, Tsultrim Allione

Tsultrim Allione

Lama Tsultrim Allione is an author and teacher who has studied in the Tibetan Buddhist lineage. She was born in 1947 in Maine, in the United States, and given the name Joan Rousmanière Ewing. She first travelled to India and Nepal in 1967, returned in 1969 and in 1970 she became one of the first...

 collected translations of the namtar of six Tibetan Buddhist yogini

Yogini

Yogini is the complete form source word of the masculine yogi- and neutral/plural "yogin." Far from being merely a gender tag to the all things yogi, "Yogini" represents both a female master practitioner of Yoga, and a formal term of respect for a category of modern female spiritual teachers in...

: Namgsa Obum, Machig Lapdron, Jomo Memo, Machig Ongjo, Drenchen Rema and A-Yu Khadro. According to Allione:

The sacred biography is called 'rNam.thar' in Tibetan, which literally means 'complete liberation.' The 'rNam.thar' are specially geared to provide records for those on a spiritual quest, in much the same way that someone about to climb a high mountain would seek out the chronicles of those who had made the climb before. The sacred biographer is primarily concerned with providing information which will be helpful and inspirational for someone following in the footsteps of the spiritual adept or 'saint.' Establishing a mythical ideal and the communication of the sacred teachings takes precedence over providing a narrative portrait or "likeness" of the subject as a personality. The personality is stressed only in so far as it relates to the spiritual process of the individual.