The purpose of this third chapter of the book is threefold. First, we present empirical patterns of policy accumulation across three areas of public policy: environmental, social and morality policy. The focus on such a diverse set of policy areas provides us with a hard test for our claim of universal policy accumulation, as we look into policy areas of widely different maturities and underlying issue complexity. In the second part of the chapter, we trace the origins of the observed pattern. This part highlights that a wide range of factors contribute collectively to the phenomenon. Policy accumulation emanates from three complementary sources: exogenously, by demand-related factors such as globalization and technological progress; endogenously, by emerging incentives on the supply-side of public policy that affect the behaviour of policy makers operating under party competition and institutional constraints; and from a self-reinforcing mechanism that is built into rule-making systems. Finally, we discuss why 'policy dementia' cannot be considered an effective antidote to policy accumulation and that some contemporary promises to reverse policy accumulation are hardly convincing.