Law enforcement analysis is increasingly utilized by police organizations to help its warranted officials understand the public safety and security environment and make decisions about threats, harms and risks. While there is a well-developed practitioner literature and a number of evaluative studies about law enforcement analysis, there has been little empirical research into the day-to-day work practice of law enforcement analysis. This thesis utilizes participant observation and semi-structured interviews to construct an ethnography of the daily work practice of law enforcement analysis in three sites in the USA, Ireland and the UK. This empirical research at the intersection of the organizational structures and work cultures of both the law enforcement analytic units and the larger police organisation to which they belong helps explain not only how knowledge is created but also what knowledge and why. The thesis concludes that while law enforcement analysis produces valuable knowledge about current threats and harms and plays a role in organizational risk management, a variety of factors circumscribe the type of knowledge that is produced. The result is that the future is left largely unknown and that law enforcement analysts play a limited role in brokering organizational uncertainty about the public safety and security environment.