Friedrich Hayek was a founding figure of the neo-liberalism that flourished in the 1980s. Yet, despite his antagonistic relationship with socialism, his work became a surprising source of inspiration for several influential thinkers on the left. This book explains the left's unusual engagement with Hayek and reflects on its significance. Engaging Enemies uses the left's late discovery of Hayek to examine the contemporary fate of socialism and social democracy. Did socialism survive the twentieth century? Did it collapse with the fall of the Berlin Wall as Hayek claimed? Or did it transform into something else, and if so what? In turn this allows an examination of ideological and historical continuity. Was the left's engagement with Hayek part of a wider break with a period of ideological continuity that marked the twentieth century, but which did not survive its ending? As such, the book is also a study of how ideologies change with the times, incorporating new elements and jettisoning others. The left's engagement with Hayek was also influential on party politics, particularly on the 'modernization' of the Labour Party and the development of New Labour. Engaging Enemies concludes with a discussion of the wider role of the market for the left today and the contemporary significance of the engagement with Hayek for Labour in the wake of the 2008 economic crisis.