This specially curated collection features four reviews of current and key research on heat stress in dairy cattle. The first chapter outlines technologies to breed for more heat tolerant dairy cattle, exploiting either between or within breed genetic variation in the trait. It discusses future perspectives on the use of different tools to achieve accelerated improvements of this important trait. The second chapter discusses breeding goals and multi-trait selection to balance production and non-production traits. It considers newer breeding objectives such as ensuring that cattle can adapt to a changing climate, including breeding for heat tolerance. The third chapter reviews challenges facing smallholder dairy farmers in Asia. These include the impact of high temperatures and humidity on milk yield, reproductive efficiency and animal health. The chapter places these challenges in the context of the broader economic constraints faced by smallholders and how they can be overcome. The final chapter highlights constraints in improving smallholder dairy production in Sub-Saharan Africa. Issues include developing breeds balancing yield with resilience to local climatic conditions. The chapter reviews ways of Improving breeding and productivity, as well as broader organisational support