The terms paper knife and letter opener are often used interchangeably to refer to a knife-like desktop tool. In truth, they are actually for different functions and were in use at different times.
Paper knives were used during the Regency period for cutting pages of books when book presses were new and not able to efficiently separate each page for reading. Letter openers "evolved" from paper knives into longer, blunter blades for the sole purpose of opening envelopes. Paper knives are no longer in common use, except perhaps by antiques enthusiasts.
An electric version of a letter opener is also available, which uses motors to slide the envelopes across a blade, and is also able to handle increased amounts of envelopes, but the blade can slice into the contents of the envelope and damage them.
Letter openers may be designed from wood, metals such as stainless steel or pewter, plastic, sometimes even ivory, or a combination of materials. Often the style of the handle is embellished or styled more so than the blade. Some modern openers have a retractable razor blade inside a plastic handle.
Patrick Henry's letter opener
American politician Patrick Henry is famous for making a speech before the Virginia House of Burgesses on March 23, 1775, stating the famous words "Give me Liberty, or give me Death!" After this, he pretended to plunge a letter opener into his chest.
Attempted assassination of MLK
Izola Curry stabbed the reverend Martin Luther King, Jr. in the chest with a letter opener on September 20, 1958, at book-signing in a Harlem department store. NYPD police officers Al Howard and Phil Romano took King in the chair down to an ambulance that took King to Harlem Hospital, and its top team of trauma surgeons, Dr. John W. V. Cordice, Jr. and Dr. Emil Naclerio. Chief of surgery Aubre de Lambert Maynard entered and attempted to remove the letter opener from King’s chest, but cut his glove on the blade; a surgical clamp was used to remove it. 
|Wikimedia Commons has media related to Letter openers.|
- A Paper Knife Was Not A Letter Opener
- Kukla, Amy; Kukla, Jon (2002). Patrick Henry: Voice of the Revolution. PowerPlus Books. pp. 45–46. ISBN 0-8239-5725-X.
- Michael Daly (January 20, 2014). "The Black and White Men Who Saved Martin Luther King’s Life". The Daily Beast. Archived from the original on 2014-01-22. Retrieved January 22, 2014.
Stabbed in the chest in 1958, one mistake or sneeze would have fatally severed his aorta if not for the deft work for two cops and two surgeons.
|This tool article is a stub. You can help Wikipedia by expanding it.|