The ILO's Encyclopaedia of Occupational Health and Safety is the most comprehensive reference source on the subject. It has a long and honourable history, having had four editions: in 1930, 1971, 1983 and 1998. It is one of the flagship publications of the International Labour Office and is widely respected worldwide by health and safety professionals, students and policy-makers alike.
The fourth edition was published in four volumes under the editorship of Prof. Jeanne Stellman. Today it is accessible online, free of charge. Few CD-ROMs with HTML versions are also available.