If your life has been touched by it, cancer can seem like the least normal thing imaginable. It disrupts all aspects of life, threatens many things we hold dear, and baffles us with its mysterious ways. It seems possessed with an uncanny ability to evade our treatments, rise from the dead when we think it's finally gone, and even hijack our bodies' resource-delivery systems to feed its growth. But cancer has been with us since the beginning of multicellular life, and it's not going anywhere. It has been a supporting character throughout humanity's story. In fact, it predates us.