Book excerpt: The study of the Polish tax system and policy which enriches knowledge of developments in one of the largest and most rapidly changing states in Europe. It is the result of cooperation of academics and practitioners from major tax advisory firms as well as in-house tax experts. Political changes in Poland (electoral victory of the right-wing PiS party) coincided with changes on the global tax scene, which were associated with the BEPS project (Base Erosion and Profit Shifting), implemented by the OECD. The struggle to rebuild countries' tax revenues began. The ambitious social policy in Poland, which involved substantial transfers of funds to the less well-off, required an increase in budget revenues. Thus, the Polish government quickly became an ardent supporter of BEPS. The radicalism of the tax policy changes raised many doubts among practitioners, who accused the authorities of excessive fiscalism. On the other hand, the legal rules previously in force did indeed poorly protect the fiscal interests of the state. The study of the Polish tax system and Polish tax policy based on the contributions collected in this volume enriches knowledge of developments in one of the largest and most rapidly changing states in Europe.