After nearly a century when electric lighting has dominated the design of building interiors, a return to the use of daylight as the main ambient light source is motivated by energy, environmental, and health considerations. Good daylighting of building interiors not only promotes low energy use, it has the potential to (re)connect humans to the natural cycle of day and night, which promotes health and well-being. Light is especially important to people in the Nordic countries because it is scarce for a large part of the year and over-abundant around the summer solstice. The unique character of daylight provided by the Nordic sky – with its weak intensity in the winter and low sun angles in the summer – demands careful study and attention, as it is more precious than in any other location.The current context of densifying cities makes it increasingly difficult to provide sufficient amounts of daylight in buildings under Nordic sky conditions, especially in winter. Analyses using advanced building simulation programs are often needed to predict daylight levels and adjust the building design accordingly. The relevant building regulations and certification schemes need to be understood in depth if they are to be followed by design practitioners. In addition, state-of-the-art electric lighting technologies such as LEDs and advanced control systems require a good integration with daylighting design. Addressing these issues, this book provides the essential knowledge and background to students and practicing professionals who wish to tackle the challenging endeavor of illuminating buildings under a Nordic sky using daylight as the main ambient light source, supplemented by energy-efficient electric lighting systems.