A postscript, abbreviated PS or P.S., is writing added after the main body of a letter (or other body of writing). The term comes from the Latin post scriptum, an expression meaning "written after" (which may be interpreted in the sense of "that which comes after the writing").

A postscript may be a sentence, a paragraph, or occasionally many paragraphs added to, often hastily and incidentally, after the signature of a letter or (sometimes) the main body of an essay or book. In a book or essay, a more carefully composed addition (e.g., for a second edition) is called an afterword. An afterword, not usually called a postscript, is written in response to critical remarks on the first edition. The word "postscript" has, poetically, been used to refer to any sort of addendum to some main work, even if it is not attached to a main work, as in Søren Kierkegaard's book titled Concluding Unscientific Postscript.

Sometimes, when additional points are made after the first postscript, abbreviations such as PPS (post-post-scriptum, or postquam-post-scriptum) and PPPS (post-post-post-scriptum, and so on, ad infinitum) are used, though only PPS has somewhat common usage.

Donald E. Lancaster is a prolific author, inventor, and microcomputer pioneer best known for his magazine columns. He is also known for his "TV Typewriter" dumb terminal project, his book on technical entrepreneurship The Incredible Secret Money Machine, and his work on and advocacy of early print-on-demand technology. Lancaster's print-on-demand technique, with which he self-published several books, employed hand-tuned PostScript code sent to a laser printer through the game port of an Apple II rather than, as was common at the time, a Macintosh running PageMaker. He helped design and manufacture the Apple I keyboard. He held a radio amateur license (K3BYG) for a short time. He sells electronic surplus on eBay and participates regularly in the eBay seller's forums.

Philip Glass (born January 31, 1937) is an American composer. One of the highest profile composers writing "classical" music today, he is often said to be one of the most influential composers of the late 20th century. His music is also often controversially described as minimalist, along with the work of the other "major minimalists" La Monte Young, Terry Riley and Steve Reich.

He has lately distanced himself from the "minimalist" label, describing himself instead as a composer of "music with repetitive structures." Though his early mature music shares much with what is normally called "minimalist", he has since evolved stylistically. Currently, he describes himself as a "Classicist", pointing out that he is trained in harmony and counterpoint and studied such composers as Franz Schubert, Johann Sebastian Bach and Wolfgang Amadeus Mozart with Nadia Boulanger.

Glass is a prolific composer: he has written works for the musical group which he founded, the Philip Glass Ensemble (with which he still performs on keyboards), as well as operas, musical theatre works, ten symphonies, eleven concertos, solo works, chamber music including string quartets and instrumental sonatas, and film scores. Three of his film scores have been nominated for Academy Awards.