A roadmap for `new policy design' studies now exists in the orientation which has emerged in recent years towards the formulation of complex policy mixes.The new design orientation focuses on bundles or portfolios of tools and the interactive effects which occur when multiple tools are used over time in policy packages designed to address multiple goals, and upon more complex multi-policy and multi-level design contexts.This review article examines the differences between the `old' instrument orientation and the `new' design one, setting out the current research agenda in this field and its rationale.