In Buddhism, kammaṭṭhāna is a Pali word (Sanskrit: karmasthana) which literally means the place of work. Figuratively it means the place within the mind where one goes in order to work on spiritual development. More concretely, it refers to the forty canonical objects of meditation (samatha kammaṭṭhāna), listed in the third chapter of the Visuddhimagga.

Each kammatthana can be prescribed, especially by a teacher (kalyāṇa-mitta), to a certain individual student at some specific point, by assessing what would be best for that student's temperament and the present state of his or her mind. 

Of the forty objects meditated upon as kammatthana, the first ten are 'things that one can behold directly', 'kasina', or 'a whole':

The next ten are objects of repulsion (asubha):

Ten are recollections (anussati):

Four are stations of Brahma (Brahma-vihara):

Four are formless states (four arūpajhānas):

One is of perception of disgust of food (aharepatikulasanna).

The last is analysis of the four elements (catudhatuvavatthana): earth (pathavi), water (apo), fire (tejo), air (vayo).

Ṭhānissaro Bhikkhu, also known as Ajaan Geoff, (born 1949) is an American Theravada Buddhist monk of the Dhammayut Order (Dhammayutika Nikaya), Thai forest kammatthana tradition. He is currently the abbot of Metta Forest Monastery in San Diego County. Ṭhānissaro Bhikkhu is a notably skilled and prolific translator of the Pāli Canon. He is also the author of many free Dhamma books.

Ṭhānissaro Bhikkhu was born Geoffrey DeGraff in 1949 and was introduced to the Buddha's teaching on the Four Noble Truths as a high schooler, during a plane ride from the Philippines. After graduating in 1971 with a degree in European Intellectual History from Oberlin College, he travelled to Thailand, where he practiced meditation under Ajaan Fuang Jotiko, who'd studied under Ajaan Lee. He was ordained in 1976 at Ajaan Lee's Wat Asokaram, where Ajaan Lee's nephew, Phra Rajvarakhun (Samrong Gunavuddho), served as Preceptor for his ordination. Later, he took residence at Wat Dhammasathit in Thailand, where he continued studying under Ajaan Fuang.