Short answers, pulled from the story.
Greene's Groats-Worth of Wit (1592) is an Elizabethan pamphlet published after Robert Greene's death, combining a moralistic tale about two brothers, Roberto and Lucanio, with a deathbed confession and sharp attacks on fellow playwrights. The narrator uses the story of Roberto's rise and ruin as a playwright to comment on his own life, then addresses three unnamed contemporaries, warning them about actors and newcomers to the stage.
The pamphlet contains a passage attacking an "upstart Crow, beautified with our feathers" who is called "the onely Shake-scene in a countrey," widely accepted as a reference to William Shakespeare. The line "Tygers hart wrapt in a Players hyde" parodies a line from Shakespeare's Henry VI, Part 3. Most scholars consider this the first documented reference to Shakespeare since 1585.
Groatsworth was entered in the Stationers' Register on the 20th of September 1592, registered "uppon the perill of Henrye Chettle." It was printed by John Danter and John Wolfe for the bookseller William Wright. Chettle claimed he had only transcribed Greene's illegible manuscript into his own hand so it could be licensed.
Authorship is disputed. Warren B. Austin's 1969 computer-aided analysis of word-choice frequencies concluded Chettle wrote the whole text, but Richard Westley in 2006 argued Austin had selected evidence to support a predetermined view and that the pamphlet was Greene's own work. Steve Mentz, writing in 2008, proposed the text was a collaboration: Greene's material substantially present but with significant editorial intervention by Chettle.
The three unnamed playwrights are generally identified as Christopher Marlowe (the "famous gracer of Tragedians" accused of atheism, educated at Corpus Christi College, Cambridge), Thomas Nashe (the "young Juvenal," educated at St John's College, Cambridge), and George Peele (educated at Christ Church, Oxford, and, like Greene, known for a chaotic lifestyle). All three were members of the University Wits, a coterie of university-educated writers associated with Greene.
Groatsworth was reprinted by Thomas Creede in 1596, four years after its first appearance in 1592. The original publication caused what contemporaries described as "a literary scandal" because of its attacks on fellow playwrights.