"Susila Budhi Dharma (Subud) and its doctrines" by Chuzaimah Batubara

This is a master thesis from McGill University but published in PDF format.  Going around 200 pages the author gives a succinct and very detail-heavy presentation of the situation in Post-Independence Indonesia, especially on the Java island which forms the core of the country and the term "Javanese" is used to imply belonging nearing ethnicity.

Javanese nationalism was reflected in the rise of "Aliran Kebatinan" so called "Mystical Movements" that originated from the animistic and Hindu original beliefs, predating Islam.  The Islam that was spread in Indonesia was an eclectic mix of heterodox Islam and the local animistic and Hindu beliefs, with a very small part of the population sticking to strict, heterodox Islam and Shari'a. 

Among the literally dozens of movements originating in this period (1920-1940), Susila Budhi Dharma (SuBuD), founded by Javanese Mohammad Subuh in 1925 was the only one that gained significant international presence and exists in significant numbers today, members numbering over 10,000 in several dozen countries.

The author describes in detail the socio-ethnic conditioning that necessitated the rise of the Aliran Kebatinan movements with their emphasis on direct, experiential link with the Higher Power, instead of through books like Islam and Christianity.  Subud was influenced by the local animistic beliefs, by the Hindu-Vedic theology (Susila = Suzila in Sanskrit, Budhi = Bodhi and Dharma is the same) ,by Mystical Sufism (where the ideas of the "nafsu" was borrowed from) and orthodox Islam. 

The author analyzes the basic concepts in Subud; like the concept of God or a Higher Power, the concept of Man and the concept of spiritual development which is done through the practical exercise "Latihan Kejuiwan" which is "channeled" for each new initiate ("opened") and usually consists of a verbal, mental, emotional and physical element. 

The thesis is very informative, if overly detailed, and gives a good overview of the milieu in which Subud arose and explains why it contains the elements it has today.