Who was Buddhadasa? Why is he Influential?

I would have to say Ajahn Buddhadasa (1906-1993) is one of my favourite Buddhist writers. 

Buddhadasa Bhikkhu ("Slave of the Buddha") remains perhaps the most influential Buddhist teacher in the history of Thailand.

He went forth  as a monk in 1926, at the age of 20. After a few years of study in Bangkok, he was inspired to live close to nature to investigate the Buddha-Dhamma as the Buddha had done. He established Suan Mokkh ("The Garden of Liberation") in 1932 near his hometown in southern Thailand. At the time it was one of the few places dedicated to vipassana meditation and the only forest Dhamma centre in the region.

He worked painstakingly to establish and explain the correct and essential principles of pristine Buddhism based on extensive research of the Pali texts, especially the Buddha's discourses (sutta pitaka), followed by personal experiment and practice with these teachings. From this, he uncovered the Dhamma which truly quenches dukkha, and which he in turn shared with anyone interested. His goal was to produce a complete set of references for present and future research and practice and his approach was always scientific, straightforward, and practical.

Although his formal education was limited to seven years, plus some preliminary Pali studies, he has been given eight Honorary Doctorates by Thai universities, and numerous Doctoral theses have been written about his work. His books fill a room at the National Library and influence all serious Thai Buddhists.

He studied all schools of Buddhism and all major religious traditions. He had a practical rather than scholarly interest - to unite all genuinely religious people (those working to overcome selfishness) to work together for world peace. He drew friends and students worldwide, including Christians, Muslims, Hindus, and Sikhs.

His other projects included an International Dhamma Hermitage where foreigners could study and practice in English, retreats in Thai, a small training centre for foreign monks, and the Dhamma Mata project to raise the status of women through better opportunities and support in Buddhist monastic life and meditation practice.

Ajahn Buddhadasa died at Suan Mokkh on July 8, 1993.