Ilmu Tajul is the most commonly used name for the Malay system of geomancy, comprising metaphysical and geomantic principles considered when siting or designing buildings to improve and maintain well-being. It was traditionally practiced by shamans (dukun or bomoh) and architects from Malaysia and Indonesia. The term actually alludes to a book entitled Tajul Muluk which covered a number of other topics including herbal medicine, astrology and dream interpretation along with geomancy. While all these subjects may be categorised under the term ilmu tajul, it usually refers to the otherwise unnamed set of rites and rules for constructing buildings in Malay culture.