Robert Baker Aitken (1917 - 2010) was the master of the Diamond Sangha, a Zen Buddhist society he founded in Honolulu in 1959 with his late wife Anne Hopkins Aitken.

     A lifetime resident of Hawai`i, Aitken Rōshi was a graduate of the University of Hawai`i with a BA degree in English literature and an MA degree in Japanese studies. In 1941, he was captured on Guam by invading Japanese forces, and interned in Japan for the duration of World War II.  In the camp, he met the British scholar R. H. Blyth , who introduced him to Zen Buddhism. After the war, he practiced Zen with Senzaki Nyogen Sensei in Los Angeles, and traveled frequently to Japan to practice in monasteries and lay centers with Nakagawa Sōen Rōshi, Yasutani Haku'un Rōshi, and Yamada Kōun Rōshi. In 1974, he was given approval to teach by the Yamada Rōshi, Abbot of the Sanbo Kyodan in Kamakura, Japan, who gave him transmission as an independent master in 1985.

     Aitken Rōshi gave full transmission as independent masters to Nelson Foster, Ring of Bone Zendo in Nevada City, California; John Tarrant , Pacific Zen Institute in Santa Rosa, California; Patrick Hawk, Zen Desert Sangha in Tucson, Arizona, and Mountain Cloud Zen Center in Santa Fe, New Mexico; Joseph Bobrow, Deep Streams Zen Institute in San Francisco, California; Jack Duffy , Three Treasures Sangha in Seattle, Washington; Augusto Alcalde, Autumn Bridge Dojo, Argentina and Rolf Drosten, Wolken-und-Mond-Sangha (Clouds and Moon Sangha) , in Leverkusen, Germany. He authorized Pia Gyger, One Ground Zendo in Luzern, Switzerland, as an affiliate teacher of the Diamond Sangha, and recognized Danan Henry as a Diamond Sangha Teacher. He joined with John Tarrant in giving transmission as independent masters to Subhana Barzaghi in Sydney, New South Wales, Australia; and to Ross Bolleter in Perth, Western Australia.

     Aitken Rōshi authored of more than ten books on Zen Buddhism, and co-authored a book-length Buddhist-Christian dialogue . In Hawai`i he was instrumental in founding the Koko An Zendo, the Pālolo Zen Center, the Maui Zendo, and the Garden Island Sangha. A number of other centers in Europe, North and South America, and Australasia are part of the Diamond Sangha network.

     As a part his commitment to making Zen Buddhism accessible to all, he paid particular attention to making a place for women, people of color, and the lgbt community. Those seeking an introduction to Zen may wish to start with Taking the Path of Zen, and those pursuing further study may benefit from his list of recommended reading.

     Aitken Rōshi was co-founder of the Buddhist Peace Fellowship (now with a local East Hawai`i Chapter) and served on its international board of advisors. He was active in a number of peace, social justice, and ecological movements, and his writing reflects his concern that Buddhists be engaged in social applications of their experience.

     As a retired master, Aitken Rōshi worked with a few long-time students, and continued to study and write until two days before his death. His work, Zen Master Raven: Sayings and Doings of a Wise Bird, was published by Tuttle in 2002  [review].  His more recent publications, The Morning Star: New and Selected Zen Writings, and a new edition of A Zen Wave: Basho's Haiku and Zen, were released in October, 2003, by Shoemaker and Hoard. In 2006, He collaborated with Daniel W.Y. Kwok and published Vegetable Roots Discourse: Wisdom from Ming China on Life and Living.

     Robert Aitken died August 5th, 2010, in Honolulu, Hawaii. His final book, The River of Heaven: The Haiku of Basho, Buson, Issa, and Shiki was published in 2011.