A book on ethical computer hacking written by a 16-year-old Indian schoolboy has sold 5,000 copies online, before it reached the shelves of bookshops around the world. The author, Ankit Fadia, wrote the book at the tender age of 14, and is the youngest author for Macmillan publishers in the company's 110 years of history. The Unofficial Guide to Ethical Hacking runs into 620 pages, and gives an in-depth look into hacking techniques, endorsing ethical hacking as a "vaccination" for "fighting evil with evil". "The book mentions tools and techniques used by hackers to break into some systems. The book throws light on unexplored horizons of the wired world, giving even the common user the information required to understand [and] counter attack hacking attempts," reads one review of the book from a technical consultant. Basing his research on his own experience and readings, Fadia -- a student at a Delhi public school -- initially started his Web site Hacking Truths for a small circle of friends to whom he would send out periodic manuals, but the site quickly evolved into a worldwide community of subscribers. The site, hackingtruths.box.sk has 16,000 registered users and more than 100,000 hits a day. It was recently judged the second best hacking site in the world by the FBI. The book deals with the nuances of the "hacker" and "cracker", but claims that real hackers are not criminals. "Hackers are the good guys who, by using their knowledge in a constructive manner, help organisations to guard their data and company secrets, and sometimes help justice by ferreting out electronic evidence of wrongdoing," says Fadia within the book. It is technical to a certain extent, and requires a minimum understanding of the Internet, Windows, TCP/IP, C++, Java and PERL. But the book has received mild criticism for not covering cryptography in enough detail. "And since it's a book on hacking and not cracking or security in general, it doesn't cover unethical topics like credit card cracking, or technology like Tempest, electronic eavesdropping or cable-drops," says a review by Fabmart books. See the Viruses and Hacking News Section for the latest headlines. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the Security forum. Let the editors know what you think in the Mailroom. And read other letters.