Short answers, pulled from the story.
Paradise Lost was first published in 1667 in ten books containing over ten thousand lines of verse. A second edition in 1674 reorganised the poem into twelve books, following the structure of Virgil's Aeneid, with minor revisions throughout.
Milton went blind in 1652 and composed Paradise Lost entirely through dictation, relying on a rotating group of amanuenses and friends. His contemporary and biographer John Aubrey placed the period of composition between 1658 and 1663.
Milton gives Satan the qualities of a classical epic hero, including an unconquerable will, military ambition, and powerful rhetoric, which led Romantic critics such as William Blake, Lord Byron, and Percy Bysshe Shelley to read him as a heroic figure. Critics like C. S. Lewis and John Carey argued against this reading, with Carey noting that Satan's ambivalence is "a precondition of the poem's success" and that any one-sided interpretation discards half the evidence.
Paradise Lost is written in unrhymed iambic pentameter, known as blank verse. Milton exploited its flexibility to create complex double syntax, using enjambment to shift meaning across line breaks. His influence was so pervasive that later poets including John Keats and Alexander Pope contended directly with it, and Samuel Johnson mocked the bad imitators it inspired.
The first illustrations were added to the fourth edition of 1688, with up to eight of the twelve prefatory engravings attributed to Sir John Baptist Medina and one to Bernard Lens II. Later notable illustrators included William Blake, Gustave Dore, Henry Fuseli, and John Martin. Salvador Dali executed a set of ten colour engravings in 1974.
Free will is one of the poem's central themes and is the basis for Milton's effort to justify God's ways to humanity. God in the poem says that Adam and Eve are "Authors to themselves in all" their judgments and choices, meaning responsibility for the Fall rests on human agency rather than divine compulsion. Critic Dennis Danielson argued in Milton's Good God (1982) that this insistence on free will directly answers charges that God's foreknowledge makes him complicit in the Fall.