''Believers in conspiracy are not discouraged by the lack of evidence, because they can easily convince themselves that the evidence has been destroyed by conspirators seeking to protect themselves or others.'' As William Hanchett suggests, believers in conspiracies are a determined and passionate lot. For more than a century now, they have been especially diligent in devising conspiracy theories to explain Lincoln's assassination. Unchecked and ignored by serious historians, they have produced hundreds of books and articles on the subject, yet have only succeeded in keeping the American public misinformed. Hanchett unravels their tangle of misconceptions and false ideas to present Lincoln's murder as the political finale to the Civil War. The assassination has seldom been considered a serious topic for historians and has never been treated with the objectivity and thoroughness Hanchett brings to bear on the subject. Allured by the confusion and mystery which have enshrouded the assassination from the beginning, other more adventurous writers have leaped into the breach with both plausible and farfetched conspiracy theories involving Confederate leaders and anti-war Democrats, Andrew Johnson or Edwin M. Stanton and the Radical Republicans, or even the leaders of the Roman Catholic Church.These authors - most notably Otto Eisenschiml whose Why Was Lincoln Murdered? (1937) inspired an entire generation of popularizers - have created theories by jumping to conclusions, presenting assumptions as facts, and ''proving'' hypotheses by distorting or manufacturing evidence. Hanchett with precision and humor puts these theories top rest and sets the record straight.''This is the best interpretation of the assassination I have ever seen in print. Hanchett realizes that these myths cannot be laid to rest by ignoring them. They must be answered directly, and his answers - so plausible that they might deceive some readers into thinking they were easily arrived at - are quite original, are the product of careful digging and clear thinking. . . . There might be a person or two in the country capable of mustering the detailed knowledge necessary to refute literature Hanchett attacks, but none, I'm certain, could do so with such graceful style.''--Mark E. Neely, Jr., director of the Louis A. Warren Lincoln Library and Museum