The Internet can appear to be elegantly designed, but as The Washington Post's Craig Timberg demonstrated in his illuminating series "Net of Insecurity," the network is much more an assemblage of kludges-more Frankenstein than Ferrari-that endure because they work, or at least work well enough. The defects hackers use often are well-known and ancient in technological terms, surviving only because of an industry-wide penchant for patching over problems rather than replacing the rot - and because Washington largely shrugged. At critical moments in the development of the Internet, some of the country's smartest minds warned leaders at the Pentagon and in Congress, but were largely ignored. The consequences now play out across cyberspace every second of every day, as hackers exploit old, poorly protected systems to scam, steal, and spy on a scale never before possible. Today, hundreds of billions of dollars are spent on computer security and the danger posed by hackers seems to grow worse each year, threatening banks, retailers, government agencies, a Hollywood studio and, experts worry, critical mechanical systems in dams, power plants, and aircraft. Many have tried to write about the origins of the Internet. But never before has a writer so thoroughly elucidated the history of the security of the Internet-and why basic flaws in its design continue to leave this country wide open to digital threats.