Fifty years ago, Doug Engelbart created a conceptual framework for augmenting human intellect in the context of problem-solving. We expand upon Engelbart's framework and use his concepts of process hierarchies and artifact augmentation for the design of personal intelligence augmentation (IA) systems within the domains of memory, motivation, decision making, and mood. This paper proposes a systematic design methodology for personal IA devices, organizes existing IA research within a logical framework, and uncovers underexplored areas of IA that could benefit from the invention of new artifacts.