Book excerpt: Intellectual Property (IP) is worth an estimated $5trn in the US alone. It covers patents, trademarks, domain names, copyrights, trade secrets and know-how. The IP of a big brand can be worth tens of billions of dollars. And yet IP is hard to value; accountants struggle with it, and banks treat it cautiously as loan collateral. Unsurprisingly, companies zealously guard their own ideas and fight to acquire those of others. Damages arising from infringements have fostered a sizeable claims industry. But IP law is complex. Protections deemed excessive to one party are seen as inadequate to another. Court decisions and interpretation of IP laws can be unpredictable, and can dramatically change the fortunes of businesses that rely on their IP - as demonstrated in the pharmaceutical industry's battle with generic drugs.This guide to intellectual property will help companies, investors, and creative thinkers understand the scope and nature of IP issues, and maximize the value from this important intangible asset.