Cities are the ideal setting for scientific exploration. They attract bright and diverse minds, are abuzz with creative activity, and can summon the capital to realize big ideas. Nature Index 2018 Science Cities profiles five science cities that are leaders in their regions. But each is contending with problems of equity and engagement that need to be addressed to keep them strong.

Creative minds drive the scientific enterprise. In recognition of their leading role, Nature Index 2018 Rising Stars profiles up-and-coming researchers in the natural sciences.

The US remains by far the largest producer of high quality Earth and environmental sciences research, but China’s output has grown rapidly since 2012 to take over second place from the United Kingdom

Nature Index 2018 Japan reveals that some of Japan’s smallest institutions are among the most efficient in the production of high quality scientific research, though the decline in Japan’s high quality scientific research output continues. The supplement examines reform efforts in light of the country’s aim to become a “super-smart” society.

Nature Index Science Inc. 2017 investigates the changing role of corporate institutions in the world of science and the costs and benefits to high-quality research of these evolving arrangements.

These are testing times for the United States. The country’s commanding scientific position is being thrown into question by the current administration’s controversial policies. Nature Index 2017 United States reveals that the country’s output of high-quality research in the natural sciences has declined over the past five years, following on from long-term declines in federal funding for research and development. At the current pace, China could overtake the US as the top contributor to the Nature Index within a decade.

Sciences thrive in cities. With two-thirds of the global population projected to live in urban areas by 2050, cities will become even more distinctly the domain of knowledge and innovation. Nature Index 2017 Science Cities explores the high-quality research being produced by 10 cities in the natural sciences. We chose them for their strong scientific credentials, metropolitan flair and global connections.

Saudi Arabia is already the scientific leader of the Arab world, but it is not standing still. Through investment in research and education — and a new focus on maximizing the commercial value of its academic prowess — the country is beating a path to reducing its reliance on oil.

Tracing the flow of scientific knowledge into economic and social benefit is a growing priority for governments and research funding agencies. Nature Index 2017 Innovation examines the connection between high-quality research and the commercialization of new products and services. In particular, it highlights the use of references to academic literature in patents to show concrete links between discovery and its economic potential.

China continues to increase its global share of research papers, but publication numbers are just one indicator that a country’s science is thriving. Nature Index 2017 China looks beyond the country’s impressive performance in key metrics and examines how it holds up in other factors that contribute to a functioning research ecosystem, such as collaboration, willingness to make data and research open, science communication and sound science policy.

Japan’s status as a science superstar is vulnerable. Nature Index 2017 Japan reveals that although the country is still among the upper echelons of global research, its output has continued to slide. This issue examines Japan’s efforts to arrest the decline and return to form as an innovative nation. The government’s structural reforms designed to negate the effects of deep university funding cuts are a start, but their effect will take time and success is far from certain.

Institutions and countries responsible for some of the highest quality science tend to form the strongest partnerships. Nature Index 2016 Collaborations highlights some of the most fruitful collaborations, such as those resulting from the bonds between China and the United States. The two countries produce the most high-quality science publications, and collaborate more than any other international pairing.