Upending everything we thought we knew about sun exposure, this trenchant investigation into the “zero-sun policy” sounds the call on the many health benefits of the sun, and what we risk when we minimize our exposure. A quiet revolution is transforming our understanding of sunlight’s effects on human health. For decades, a “zero-sun” policy has characterized our approach to sun protection, advising us to stay out of the sun whenever possible and apply sunscreen daily to any skin that might be exposed, rain or shine, summer or winter, indoors or out. But recent studies have proved that this policy is thoroughly mistaken and that this prolific misunderstanding is causing us to miss out on many of the health benefits of sun exposure. In this incisive work, acclaimed journalist Rowan Jacobsen presents the growing case for the importance of modest sun exposure for our health and well-being. Aided by the most up-to-date studies on the effects of sunlight on human health, Jacobsen presents a much-needed, lucid assessment of not only what the sun can do for us, but how a lack of sun could actively be harming us. In Defense of Sunlight sounds the call on what researchers have been sure of for years, and what health care providers and media outlets have been slow to take up: that sunlight is one of the simplest, and most equitable, treatments for a variety of health issues, from diabetes to dementia to multiple sclerosis. Laying out the new science of sunlight in a straightforward and responsible manner for mainstream readers, this book is an eye-opening story of scientific discovery, outlining not only best practices for sun exposure, but the story of how current recommendations became misguided, how a few inquisitive scientists glimpsed the truth and deciphered the mechanisms responsible, and how everyone can safely incorporate this new knowledge into their daily lives. It also exposes the implicit injustice underlying current approaches, which benefit the whitest people on earth (who are the most susceptible to skin cancer) at the expense of those with darker skin (who suffer extremely low rates of skin cancer and have the most to gain from sun exposure). A call for a return to common sense in our relationship with our local star, In Defense of Sunlight offers its own seven words of advice: Get sun. Not too much. Go outside.