Teachers are listed below in roughly chronological order. For some notes on the names and titles of Thai monks, see the endnotes.[1]

From the Kammathana[2] forest tradition:

Sao Kantasilo, Phra Ajaan (1861-1941)

Ajaan Sao and his student Ajaan Mun established the Kammatthana tradition. A true forest-dweller, Ajaan Sao left no written records of his teachings. Another of his students — Phra Ajaan Phut Thaniyo — did, however, record some of them in Ajaan Sao's Teaching: A Reminiscence of Phra Ajaan Sao Kantasilo, giving us a tantalizing glimpse into Ajaan Sao's terse but powerful teaching style.

Mun Bhuridatto, Phra Ajaan (1870-1949)

Ajaan Mun was born in 1870 in Baan Kham Bong, a farming village in Ubon Ratchathani province, northeastern Thailand. Ordained as a Buddhist monk in 1893, he spent the remainder of his life wandering through Thailand, Burma, and Laos, dwelling for the most part in the forest, engaged in the practice of meditation. He attracted an enormous following of students and, together with his teacher, Phra Ajaan Sao Kantasilo Mahathera (1861-1941), established the forest meditation tradition (the Kammatthana tradition) that subsequently spread throughout Thailand and to several countries abroad. He passed away in 1949 at Wat Suddhavasa, Sakon Nakhorn province.

— Adapted from A Heart Released.

A newly revised biography of Ajaan Mun, written by Ajaan Maha Boowa, is available from Wat Pah Baan Taad. For more about Ajaan Mun and the history of the Kammatthana tradition, see the essay "The Customs of the Noble Ones," by Thanissaro Bhikkhu.

Dune Atulo, Phra Ajaan (1888-1983)

Ajaan Dune Atulo was born on October 4, 1888 in Praasaat Village in Muang District, Surin province. At the age of 22 he ordained in the provincial capital. Six years later, disillusioned with his life as an uneducated town monk, he left to study in Ubon Ratchathani, where he befriended Ajaan Singh Khantiyagamo and reordained in the Dhammayut sect. Shortly thereafter, he and Ajaan Singh met Ajaan Mun, who had just returned to the Northeast after many years of wandering. Impressed with Ajaan Mun's teachings and with his deportment, both monks abandoned their studies and took up the wandering meditation life under his guidance. They were thus his first two disciples. After wandering for 19 years through the forests and mountains of Thailand and Cambodia, Ajaan Dune received an order from his ecclesiastical superiors to head a combined study and practice monastery in Surin. It was thus that he took over the abbotship of Wat Burapha, in the middle of the town, in 1934. There he remained until his death in 1983.

— From Gifts He Left Behind.

Thate Desaransi, Phra Ajaan (1902-1994)

Ajaan Thate was internationally recognized as a master of meditation. In addition to his large following in Thailand, Ajaan Thate has trained many western disciples.

Lee Dhammadharo, Phra Ajaan (1907-1961)

Ajaan Lee was one of the foremost teachers in the Thai forest ascetic tradition of meditation founded at the turn of the century by his teacher, Phra Ajaan Mun Bhuridatta. His life was short but eventful. Known for his skill as a teacher and his mastery of supranatural powers, he was the first to bring the ascetic tradition out of the forests of the Mekhong basin and into the mainstream of Thai society in central Thailand.

— From The Autobiography of Phra Ajaan Lee.

Khamdee Pabhaso, Phra Ajaan (1902-1984)

Ajaan Khamdee was born into a farming family in Khon Kaen province in northeastern Thailand. At the age of 22 he ordained at the local temple in line with Thai custom, but was dissatisfied with the type of practice customary at village temples. As a result, in 1928 he reordained in the Dhammayut sect, and in the following year became a student of Ajaan Singh Khantiyagamo, a senior disciple of Ajaan Mun. Taking up the life of a wandering monk, he sought out quiet places in various parts of northeastern Thailand until coming to Tham Phaa Puu (Grandfather Cliff Cave) in Loei province, near the Laotian border, in 1955. Finding it an ideal place to practice, he stayed there for most of the remainder of his life, moving down to the foot of the hill below the cave when he became too old to negotiate the climb.

Well-known as a teacher of strong character and gentle temperament, he attracted a large following of students, both lay and ordained. By the time of his death, a sizable monastery had grown up around him at the foot of Grandfather Cliff.

— From Making the Dhamma Your Own.

Sim Buddhacaro, Phra Ajaan (1909-1992)

Looang Boo Sim Buddhacaro was born on the 26th November 1909 in Sakhon Nakhon Province, North-East Thailand. His parents were farmers and dedicated supporters of the local monastery. At the age of 17 Looang Boo Sim took novice ordination and shortly afterwards became a disciple of the Ajaan Mun. Looang Boo Sim stayed with Ajaan Mun and various of his senior disciples for many years, taking full ordination at the age of 20 at Wat Sri Candaravasa, Khon Kaen.

In later years he was the Abbot of a number of monasteries in various parts of Thailand and was given the ecclesiastical title of Phra Khroo Santivaranana in 1959. In 1967 he established a monastery in the remote mountains of Chiang Dao in Chiang Mai province that remained his residence until his death in 1992.

— Adapted from Simply So.

Maha Boowa Ñanasampanno, Phra Ajaan (1913-2011)

Venerable Ajaan Maha Boowa was born in Udorn-thani, North-east Thailand in 1913. He became a monk in the customary way at a local monastery and went on to study the Pali language and texts. At this time he also started to meditate but had not yet found a suitable Teacher. Then he caught sight of the Ven. Ajaan Mun and immediately felt that this was someone really special, someone who obviously had achieved something from his Dhamma practice.

After finishing his Grade Three Pali studies he therefore left the study monastery and followed Ven. Ajaan Mun into the forests of N.E. Thailand. When he caught up with Ven. Ajaan Mun, he was told to put his academic knowledge to one side and concentrate on meditation. And that was what he did. He often went into solitary retreat in the mountains and jungle but always returned for help and advice from Ven. Ajaan Mun. He stayed with Ven. Ajaan Mun for seven years, right until the Ven. Ajaan's passing away.

The vigor and uncompromising determination of his Dhamma practice attracted other monks dedicated to meditation and this eventually resulted in the founding of Wat Pa Bahn Tahd, in some forest near the village where he was born. This enabled his mother to come and live as a nun at the monastery.

Ven. Ajaan Maha Boowa is well known for the fluency and skill of his Dhamma talks, and their direct and dynamic approach. They obviously reflect his own attitude and the way he personally practiced Dhamma. This is best exemplified in the Dhamma talks he gives to those who go to meditate at Wat Pa Bahn Tahd. Such talks usually take place in the cool of the evening, with lamps lit and the only sound being the insects and cicadas in the surrounding jungle. He often begins the Dhamma talk with a few moments of stillness — this is the most preparation he needs — and then quietly begins the Dhamma exposition. As the theme naturally develops, the pace quickens and those listening increasingly feel its strength and depth.

The formal Dhamma talk might last from thirty-five to sixty minutes. Then, after a more general talk, the listeners would all go back to their solitary huts in the jungle to continue the practice, to try to find the Dhamma they had been listening about — inside themselves.

— From To the Last Breath.

Fuang Jotiko, Phra Ajaan (1915-1986)

Ajaan Fuang was one of Ajaan Lee's most devoted students, spending some 24 rains retreats in the company of his renowned teacher. After Ajaan Lee's death, Ajaan Fuang continued on at Wat Asokaram, Ajaan Lee's bustling monastery near Bangkok. A true forest monk at heart, Ajaan Fuang left Wat Asokaram in 1965 in search of greater solitude more conducive to meditation, and ultimately ended up at Wat Dhammasathit in Rayong province, where he lived as abbot until his death in 1986.

— Adapted from Awareness Itself.

Chah Subhaddo, Phra Ajaan (1918-1992)

Ajaan Chah was born in 1918 in a village in the northeastern part of Thailand. He became a novice at a young age and received higher ordination at the age of twenty. He followed the austere Forest Tradition for years, living in forests and begging for almsfood as he wandered about on mendicant pilgrimage. He practiced meditation under a number of masters, including Ajaan Mun, who had an indelible influence on Ajaan Chah, giving his meditation the direction and clarity that it lacked. Ajaan Chah later became an accomplished meditation teacher in his own right, sharing his realization of the Dhamma with those who sought it. The essence of the teaching was rather simple: be mindful, don't hang on to anything, let go and surrender to the way things are.

Ajaan Chah's simple yet profound teaching style had a special appeal to Westerners, and in 1975 he established Wat Pah Nanachat, a special training monastery for the growing number of Westerners who sought to practice with him. In 1979 the first of several branch monasteries in Europe was established in Sussex, England by his senior Western disciples (among them Ajaan Sumedho, who is presently senior incumbent at the Amaravati Buddhist Monastery, England). Today there are ten branch monasteries in Europe, Australia, and New Zealand.

Ajaan Chah passed away in January, 1992 following a long illness.

— Adapted from A Tree in a Forest (Chungli, Taiwan: Dhamma Garden, 1994) and Bodhinyana.

Suwat Suvaco, Phra Ajaan (1919-2002)

Born on August 29, 1919, Ajaan Suwat ordained at the age of 20 and became a student of Ajaan Funn Acaro two or three years later. He also studied briefly with Ajaan Mun. Following Ajaan Funn's death in 1977, Ajaan Suwat stayed on at the monastery to supervise his teacher's royal funeral and the construction of a monument and museum in Ajaan Funn's honor. In the 1980's Ajaan Suwat came to the United States, where he established four monasteries: one near Seattle, Washington; two near Los Angeles; and one in the hills of San Diego County (Metta Forest Monastery). He returned to Thailand in 1996, and died in Buriram on April 5, 2002 after a long illness.

From other Thai traditions:

Kee Nanayon, Upasika (Kor Khao-suan-luang) (1901-1979)

Upasika Kee Nanayon, who wrote under the penname, K. Khao-suan-luang, was one of the foremost woman teachers of Dhamma in modern Thailand. Born in 1901, she started a practice center for women in 1945 on a hill in the province of Rajburi, to the west of Bangkok, where she lived until her death in 1979. Known for the simplicity of her way of life, and for the direct, uncompromising style of her teaching, she had a way with words evident not only in her talks, which attracted listeners from all over Thailand, but also in her poetry, which was widely published.

Nararatana Rajamanit, Chao Khun (Tryk Dhammavitakko) (1898-1971)

Prior to his ordination, Chao Khun Nararatana was a member of King Rama VI's personal staff, and was so trusted by the king that he was given the rank of Chao Phraya — the highest Thai rank of conferred nobility — when he was only 25. After the king's death in 1926, he ordained at Wat Thepsirin in Bangkok, and remained a monk until passing away from cancer in 1971. From the year 1936 until his death, he never left the wat compound. Even though the wat was one of the most lavishly endowed temples in Bangkok, Chao Khun Nararatana lived a life of exemplary austerity and was well known for his meditative powers. He left no personal students, however, and very few writings.

— From An Iridescence on the Water.