The National Academies have made available for free online the 196 page book, Macondo Well-Deepwater Horizon Blowout: Lessons for Offshore Drilling Safety. After examining the causes of the blowout, the report makes recommendations for the oil and gas industry and government regulators and advises taking a "system safety" approach "anticipating and managing possible dangers at every level of operation."
A paperback version is also available for purchase from the National Academies website.