.- 1. Introduction.- 2. Finding a Role.- 3. Science and strategy: innovation and influence, 1880-1891.- 4. The growth of international influence, 1892-1899.- 5. Public health and the 'crisis' in Edwardian government, 1900-1908.- 6. A new approach: challenges and opportunities in a changing world, 1908-1919.- 7. Conclusion.