Hinayana or "foundational" Buddhism
The term Hinayana ("Low Vehicle," "Lesser Vehicle") refers to the group of Buddhist schools or sects that appeared before the common era and those schools or sects that were later derived from them. Hinayana was originally a pejorative term used by supporters of the Mahayana ("Great Vehicle," discussed below) to describe those who did not accept Mahayana teachings as the authentic words of the Buddha. As modern scholars have not yet successfully coined a term to replace it, Hinayana is also often used in a nonpejorative sense to refer to the more than twenty defunct non-Mahayana schools of Indian Buddhism. In this essay, the term foundational Buddhism has been used as a replacement for Hinayana Buddhism. Foundational Buddhist schools emphasize the attainment of salvation for oneself, through individual effort, and the necessity of monastic life in order to attain spiritual release.

Theravada Buddhism
Theravada ("Way of the Elders") is a branch of the Indian Sthaviravada Buddhist school that was established in Sri Lanka in the third century B.C.E. Although the school died out in India, Theravada became the most popular form of Buddhism in Sri Lanka by the eleventh century, and by the twelfth century, it was the dominant form in Southeast Asia. Although Theravada is sometimes used to replace the pejorative term Hinayana, in actuality Theravada Buddhism is the last remaining school of the twenty or so early Indian non-Mahayana schools of Buddhism to survive and is not an adequate substitute. Theravada practice focuses primarily on meditation and concentration, and it is centered on monastic life, which is thought to be a superior way of achieving liberation than the life of a layman. Theravada stresses worship of the three jewels (triratna): the Shakyamuni Buddha, the monastic community (sangha), and the Buddhist doctrine (dharma). The highest ideal is that of the arhat, the monk who attains enlightenment by meticulously following the teachings of the Buddha.

Mahayana Buddhism
Mahayana ("Great Vehicle") is a term used by proponents of texts that began to appear roughly four centuries after the death of the Buddha. The texts were regarded as the word of the Buddha. Mahayana has come to mean by extension those forms of Buddhism (today located for the most part in Tibet, China, Korea, and Japan) that base their practice on these texts. Although once believed to be much later than Hinayana (foundational) Buddhism, Mahayana co-existed with it at a very early time. The bodhisattva is the ideal in Mahayana Buddhism. Bodhisattvas are beings who are able to escape the endless cycle of birth, death, and rebirth known as samsara but choose to remain active in the world to help others along the path to enlightenment. According to the Mahayana, followers of foundational Buddhism selfishly pursued only their own personal salvation rather than following what Mahayanists believe to be the superior path of the bodhisattva, the all-compassionate hero who, resolving to become a Buddha in some far-distant future, dedicates countless lives to saving all beings. Mahayana Buddhism postulates an expanded pantheon that includes innumerable bodhisattvas and multiple buddhas.

Vajrayana Buddhism
The Vajrayana ("Diamond Vehicle," "Thunderbolt Vehicle") form of Buddhism, also known as Esoteric Buddhism or Tantric Buddhism, is the latest of three major forms of Buddhism to have developed. Vajrayana Buddhism expands the pantheon even further than Mahayana Buddhism and stresses the ability to attain enlightenment, and thus liberation from the endless cycle of rebirth, in just one lifetime. Some of the methods for achieving such a fast enlightenment include esoteric practices that require extensive training on the part of the aspirant and depend on teachings given directly from master to disciple. Although Vajrayana Buddhism may have originated in India as early as the third century C.E., it became more widely practiced only during the eighth and ninth centuries. After the eighth century, Vajrayana Buddhism was not only strongly entrenched in eastern India, it spread to Nepal and Tibet (which became a center for Vajrayana Buddhism as well as the major storehouse of its literature), flourished briefly in China, became highly influential in Japan, and would be the basis for a famous monastic university in Indonesia.

Pure Land Buddhism
A pure land, which is also known as a buddha field, is a domain created by a buddha as an ideal setting for the practice of Buddhism. In Mahayana and Vajrayana Buddhism pure lands function as a form of paradise and rebirth in one, particularly that of the Buddha Amitabha, which was the focus of various practices, especially in East Asia. Most important was the recitation of the name of Amitabha (Japanese: Amida), particularly at the moment of death, to ensure rebirth in his Western Paradise. Although it has Indian antecedents, Pure Land Buddhism began to be popular in China in the sixth century. Its popularity quickly escalated, due in part to the instability of the political situation, which devotees believed was a sign of the decline of the Buddhist doctrine (dharma).