This book is a political history of the island of Malaita in the British Solomon Islands Protectorate from 1927, when the last violent resistance to colonial rule was crushed, to 1953 and the inauguration of the island’s first representative political body, the Malaita Council. At the book’s heart is a political movement known as Maasina Rule, which dominated political affairs in the southeastern Solomons for many years after World War II. The movement’s ideology, kastom, was grounded in the determination that only Malaitans themselves could properly chart their future through application of Malaitan sensibilities and methods, free from British interference. Kastom promoted a radical transformation of Malaitan lives by sweeping social engineering projects and alternative governing and legal structures. When the government tried to suppress Maasina Rule through force, its followers brought colonial administration on the island to a halt for several years through a labour strike and massive civil resistance actions that overflowed government prison camps. David Akin draws on extensive archival and field research to present a practice-based analysis of colonial officers’ interactions with Malaitans in the years leading up to and during Maasina Rule. A primary focus is the place of knowledge in the colonial administration. Many scholars have explored how various regimes deployed “colonial knowledge” of subject populations in Asia and Africa to reorder and rule them. The British imported to the Solomons models for “native administration” based on such an approach, particularly schemes of indirect rule developed in Africa. The concept of “custom” was basic to these schemes and to European understandings of Melanesians, and it was made the lynchpin of government policies that granted limited political roles to local ideas and practices. Officers knew very little about Malaitan cultures, however, and Malaitans seized the opportunity to transform custom into kastom, as the foundation for a new society. The book’s overarching topic is the dangerous road that colonial ignorance paved for policy makers, from young cadets in the field to high officials in distant Fiji and London. Today kastom remains a powerful concept on Malaita, but continued confusion regarding its origins, history, and meanings hampers understandings of contemporary Malaitan politics and of Malaitan people’s ongoing, problematic relations with the state.