The 5-year Circum-Arctic Lithosphere Evolution (CALE) program developed new constraints on the tectonic history of the central Amerasia basin of the Arctic Ocean. This volume is the final synthesis of the CALE program, which brought together an international team of scientists to develop integrated, multi-disciplinary understanding of the region. This approach, based on the integration of much new geological and geophysical data from onshore and offshore , is necessary to advance our understanding of this basin. Regional onshore-to-offshore transects are central to the 18 papers in this volume. The diverse science supporting these crust-to-mantle regional transects includes structural, geochronological, isotopic, potential fields, and seismic reflection and refraction data. Four chapters present circum-Arctic investigations by the regional CALE teams. The final chapter addresses pan-Arctic themes. This unique collaboration, relying on new data and new syntheses of existing data sheds new light on the history of the Arctic Ocean.