The OECD Programme for International Student Assessment (PISA) examines what students know in reading, mathematics and science, and what they can do with what they know. It provides the most comprehensive and rigorous international assessment of student learning outcomes to date. Results from PISA indicate the quality and equity of learning outcomes attained around the world, and allow educators and policy makers to learn from the policies and practices applied in other countries. PISA 2018 findings showed that 15-year-old students in four provinces/municipalities of China -- Beijing, Shanghai, Jiangsu and Zhejiang -- outperformed their peers in all of the other 78 participating education systems -- in mathematics and science by a wide margin, and in reading, only Singapore came close. In fact, the 10% most disadvantaged students in these four provinces showed better reading skills than those of the average student in OECD countries, and performed on a par with the 10% most advantaged students in some of them. The size of each compares to that of a typical OECD country, and their combined populations amount to over 180 million. What makes their achievement even more remarkable is that the level of income of these four Chinese regions is well below the OECD average. At the same time, they have a long way to go when it comes to improving the social and emotional outcomes, and other aspects of students' well-being that were measured by PISA 2018, areas where other countries excel (more on that later). Findings also showed that some of today's highest-performing education systems have only recently attained their top positions. Some countries were able to move to a more positive trajectory in recent years after a period of stagnation or decline. PISA also shows that in most countries excellence in education is apparent amongst some of the most disadvantaged students and schools. Factors that PISA shows to be positively associated with academic resilience include support from parents, a positive school climate and having a growth mindset. When comparing countries that score similarly in PISA, their income levels vary widely. History shows that countries with the determination to build a first-class education system can achieve this even in adverse economic circumstances, and their schools today will be their economy and society tomorrow. This summary report highlights the major findings of PISA 2018 while addressing topics such as new technologies; building strong foundations; reconciling equity and excellence; fostering a growth mindset; aligning education and career aspirations; and school life, student life, and well-being. [For the first three volumes of "PISA 2018 Results," see ED601138, ED601139, and ED601142, respectively.]