Liver resections involve removing part of the liver. The liver is an essential organ but has a remarkable reserve and ability to compensate. Contrary to popular belief, the liver does not "grow back" after surgery. However the remaining liver gets bigger. Reasons for liver resections include benign tumours and cancers, including primary cancers arising within the liver, and cancers having spread to the liver from somewhere else ("metastases"), most commonly from the bowel. Liver resections range from relatively minor, to very complex and major, requiring long hospital stays and sometimes intensive care. Some liver resections can be performed laparoscopically ("key hole"). Occasionally, liver resections can be combined with ablations, where energy devices such as microwaves are used during the operation to destroy some tumours. Treatment of liver cancers is complex and requires coordination across specialties including radiology, gastroenterology, surgery, and oncology.