Radiation is all around us all the time, and some of it is the kind of stuff that smashes into our DNA and damages it. But don’t worry – it’s rarely present in sufficient doses to do us any harm in our day-to-day lives. In fact, we’ve developed technologies that can harness damaging X-rays and other forms of ionising radiation for the good of humankind. In this issue of How It Works, we explore the deadly yet fascinating extreme end of the electromagnetic spectrum, home to invisible alpha, beta, gamma and neutron rays. Discover both natural and human-made sources of radiation, and how we can detect and protect ourselves from it. Plus, two free How It Works specials worth £25 for every reader.