Irelands Naturall History, written by the Dutch physician Gerard Boate, is a key document in the history of science during the seventeenth century. Yet, scholars have undermined its significance in the Cromwellian resettlement of Ireland and its influence on colonial projects under the umbrella of ‘science’ during the 1650s. The interconnections between the advancement of the new learning during a period of political turmoil that began with the Irish rebellion of 1641 raises new questions for colonial narratives. Thus, re-examining the significance of Irelands Naturall History also raises new perspectives on the meaning of science during the Cromwellian reconquest of Ireland. From its initial composition to its legacy in the eighteenth century, Irelands Naturall History is a multi-faceted work that served many purposes – from a guide to a successful plantation to a source on the improvement of the Irish landscape.