Almost one hundred years ago Dutch colonialism stumbled into one of its lengthiest, bloodiest, and most costly struggles: the subjection of north Sumatra, Atjeh in particular. The two books under review (both published in 1969) throw new light on this important encounter and in many ways complement each other. Anthony Reid's work (based on a doctoral dissertation submitted to Cambridge in 1965) focusses on the Atjeh war and surrounding diplomatic events during 1870-1898. Reid precedes this with a brief survey of the contest about the East Coast of Sumatra which culminated in the Siak Treaty of 1858. Although Dutch control as a result of this treaty was extended as far north as Atjeh's southeastern dependencies, the Dutch were able to pacify British opposition (vigorously expressed by the merchants of Penang) by introducing a nondifferential tariff in the whole region (p. 29). North Sumatra was a different matter. Its people were warlike, more unified, and marked with religious zeal. Its trade at this time was almost entirely with Britain's Penang entrepot. At the same time the Treaty of London of 1824 denied both Britain and the Netherlands political control.