This book synthesises recent work by the OECD analysing services trade policies and quantifying their impacts on imports and exports, the performance of manufacturing and services sectors, and how services trade restrictions influence the decisions and outcomes of firms engaged in international markets. Based on the OECD Services Trade Restrictiveness Index (STRI) - a unique, evidence-based tool that provides snapshots of regulations affecting trade in services in 22 sectors across 44 countries (representing over 80% of global trade in services) - the analysis highlights the magnitude, nature and impact of the costs entailed by restrictive services trade policies. The new evidence uncovered is meant to inform trade policy makers and the private sector about the likely effects of unilateral or concerted regulatory reforms and help prioritise policy action.