Book excerpt: Collecting autographs is a time-honored avocation that has exploded in popularity in recent years, creating a new industry with millions of autographed items for sale online. Coveted signatures include those of United States presidents, Civil War officers, World War II heroes, classical music composers and baseball stars. It has been estimated that 90 percent of historical autographs on the market today are forgeries. This book is a definitive guide to signature authentication for experts and beginners alike. Numerous illustrations of both genuine and forged signatures are included, from Ty Cobb to Abraham Lincoln to Isaac Newton to Neil Armstrong. Detailed descriptions of common forgeries are given, enabling collectors to make direct comparisons.