The primary brief for work on this report was to explore the factors that have led New Zealand to have a high incarceration rate and the associated impacts on the capital cost of prisons. Data for the reports were sourced from the Ministry of Justice and the Integrated Data Initiative. The first drafts were prepared by the Science Advisor to the Justice Sector, Associate Professor Ian Lambie, who has been working in the justice sector for 30 years, assisted by the Chief Science Advisor, Sir Peter Gluckman. Subsequent drafts have incorporated comments and inputs from other departmental science advisors. This is the first of two reports: it discusses the general issues and factors related to exploding prison population and costs. The second report, which will be released within the next month, explores factors that are particularly relevant to youth offenders. (Foreword). Record #5817