The early editions usually capitalize ‘Heaven’, and they make no typographical distinction between God’s empyreal Heaven and the stellar heavens of the created universe. I have used the upper case for God’s Heaven and the lower case for the heavens below the primum mobile. The justification for this typographical distinction is that it can serve the modern reader as a helpful guide (see e.g. Paradise Lost ii 1004–6 and vii 162–7). Modern-spelling editions invariably make such a distinction between ‘God’ and ‘god’, even though the early texts use the upper case for pagan gods as well as God.

My prime purpose in the notes has been to elucidate Milton’s biblical, classical, historical and other allusions. I have also attempted to illustrate Milton’s verbal inventiveness by frequent recourse to the Oxford English Dictionary. Like Shakespeare, Milton added many words and phrases to the language. Many of these have become so integrated into standard English that the modern reader is not surprised by them; yet Milton may have meant them to surprise. Some of Milton’s coinages have become clichés, and we must make an imaginative effort to hear them afresh. ‘Pandaemonium’ is the most famous example. Others are less well known, but no less significant. Lost in the woods at night, the Lady in A Masque catches a glimpse of the moon behind a cloud and asks:

Was I deceived, or did a sable cloud
Turn forth her silver lining on the night? (221–2)

This is the OED’s earliest instance of what has since become a hackneyed metaphor.

In my notes I have marked Milton’s neologisms with an asterisk. When the OED credits Milton with the first use of a word, I place the asterisk immediately before the word, as in my note to Paradise Lost i 548:

*serried pressed close together, shoulder to shoulder.

When the OED credits Milton with using an existing word in a new sense, I place the asterisk before the sense, as in my note to Paradise Lost ii 439:

unessential *possessing no essence (OED 1).

I have checked every word in Milton’s English poems against the OED, but my asterisks should still be used with caution. Although the editors of the OED attempted to record the first use of every word, they inevitably made some errors. William B. Hunter has identified some of these in his seminal essay ‘New Words in Milton’s English Poems’.3 Hunter nevertheless found the OED to be reliable in the vast majority of cases. Out of more than one thousand words and senses ‘apparently original in some sense with Milton’, Hunter found only twenty-eight cases where the OED was in error. Hunter was writing in 1954. Preparing my edition in the 1990s, I have been able to use the enormous searching-power of the OED on CD ROM. With just a few keystrokes it has been possible to check Milton’s putative neologisms against all quotations in the OED. Sometimes the OED credits Milton with a new word, not knowing that it is quoted in an earlier text elsewhere in the dictionary. The OED credits Milton with coining ‘loquacious’ in Paradise Lost x 161, but a global search of all OED quotations finds an earlier instance from 1656. Sometimes Milton antedates the OED’s first instance. The OED’s earliest instance of ‘self-esteem’ is from 1657, but Milton had used the term in An Apology for Smectymnuus (1642). In my note to Paradise Lost viii 572 I accordingly mark ‘self-esteem’ with an asterisk and note that Milton may have coined the term in his prose. I have silently omitted any neologism that the OED falsely accredits to Milton.

The OED can also alert the modern reader to words that have changed or narrowed their meaning since Milton’s time. English is rich in words that mean the opposite of themselves, and Milton loves to pun on words of this kind. In one case an entire poem hinges on such a word. The poem is Sonnet XII (‘I did but prompt the age to quit their clogs’). Milton wrote it in 1646, after his divorce pamphlets had caused a scandal.