This is an open access title. It is available to read and download as a free PDF version at Oxford Medicine Online. It has been made available under a Creative Commons Attribution-Non Commercial [No Derivatives] 4.0 International licence.Before new interventions are released into disease control programmes, it is essential that they are carefully evaluated in "field trials". These may be complex and expensive undertakings, requiring the follow-up of hundreds, or thousands, of individuals, often for long periods. Descriptions of thedetailed procedures and methods used in the trials that have been conducted have rarely been published. A consequence of this, individuals planning such trials have few guidelines available and little access to knowledge accumulated previously, other than their own. In this manual, practical issues in trial design and conduct are discussed fully and in sufficient detail, that Field Trials of Health Interventions may be used as a "toolbox" by field investigators. It has been compiled by an international group of over 30 authors with direct experience in thedesign, conduct, and analysis of field trials in low and middle income countries and is based on their accumulated knowledge and experience.Available as an open access book via Oxford Medicine Online, this new edition is a comprehensive revision, incorporating the new developments that have taken place in recent years with respect to trials, including seven new chapters on subjects ranging from trial governance, and preliminary studiesto pilot testing.