What are the patent wars? Apple and Samsung return to court on Thursday, as the South Korean group attempts to overturn a verdict in August that found it guilty of infringing Apple's patents and product characteristics. This long-running battle between two of tech's biggest groups has placed renewed focus on intellectual property and the rise of patent litigation within the smartphone industry in recent years. Richard Waters, the FT's West Coast editor, traces the history of patent litigation within the technology sector and asks if the patent valuation bubble is finally close to bursting. Photo credits: Getty, Reuters and AP