Police detectives and other law enforcement agents approach each new case carefully, knowing that not every crime - whether murder, disappearance, robbery, or other transgression of the law - can be solved. By carefully collecting and examining evidence, rigorously interrogating suspects, and following up every lead with smart sleuthing, investigators are able to solve most crimes, even some that first appear to be extremely mysterious and troubling. However, true crime readers, crime buffs, students, and readers interested in the history of law enforcement and criminal investigations know that some cases stump the experts. The Encyclopedia of Unsolved Crimes details more than 540 of the most baffling cases of the past two centuries from around the world. This fascinating resource delves into legendary unsolved crimes as well as many disturbing cases from the 19th and 20th centuries that have continued to spark interest among crime writers, professional investigators, and amateur crime sleuths. Entries provide an overview of the crime, the parties involved, the evidence gathered, and the leading theories of law enforcement. Topics such as missing persons are also discussed. Focusing on cases involving prominent figures (Jimmy Hoffa) and mysterious scenarios (the Zodiac Killer) as well as those with a major social impact (the Tylenol Murders), The Encyclopedia of Unsolved Crimes offers comprehensive and valuable coverage.