The etymology of the word "Sahel" is traced back to an Arabic word meaning "coast" or "shore". Historically, the Sahel region has been an international cross-roads for trade and until recently there was free movement of people in the region, but recent crackdowns following shifts in migration policies in Europe have left many trapped. Additionally, the region is troubled by insecurity, including prolonged armed conflicts and other situations of violence and transnational crime. This is exacerbated by the devastating effects of climate change. The consequences of these overlapping crises in the region have affected millions of families, who find themselves caught up in multiple coinciding crises.Insecurity is closely related to widespread poverty, economic and developmental issues. According to a 2017 study of civil society in Mali, lack of employment opportunities was perceived as the number one security threat. High unemployment is only expected to get worse. Three-quarters of the region's population are under the age of 35, and the population is expected to double in the next 30 years. Furthermore, climate change is shrinking the area of land suitable for farming and water is increasingly scarce. The lives and livelihoods of millions of people are jeopardized by poor harvests and lack of feed for livestock.In an area of the world with porous borders, threats are increasingly addressed regionally. The G5 Sahel, created in 2014, is a framework for regional cooperation between Mauritania, Mali, Niger, Burkina Faso and Chad. Notably, the Joint Force G5 Sahel, heavily supported by France, Germany and others was launched in 2017 to combat terrorism, as well as organized crime, notably drug and human trafficking. The use of force by the Joint Force G5 Sahel raises important legal questions, given its dual law enforcement and combat roles.This issue of the Review will examine the formidable interrelated challenges faced in the Sahel region and the initiatives aimed at addressing them. Indeed, the Sahel is a microcosm of the problems faced in contemporary armed conflicts around the world. Despite the challenges, there is also much potential in the Sahel, notably from the strong sense of citizen engagement demonstrated by civil societies, which have mobilized to establish initiatives aimed at peace, development and de-radicalization.The Review will highlight the agency and resilience of local populations, privileging contributions from authors in the region. Contributions in French are encouraged.Authors are invited to send submissions to the Review's editorial team, preferable in the form of a word document, at review@icrc.org. The deadline for submissions is 31 January 2020. Additional guidelines for authors are available here.