In an earlier post I wrote a little about Browning's Childe Roland to the Dark Tower Came. The title of Browning's poem ought to include its sub-titular note, thus:
These are the first four stanzas of the poem Google's digitization of one of the first editions of Browning's Men and Women. Notice the fact that the title is in quotation marks, and in caps; that the note is parenthetical but capitalized like a title; and that Lear (I won't put, oh let's call them... mentioning marks around it, because I think the poem somewhat erodes the distinction between use and mention; and because I will be reproducing other mentioning marks in order to mention them)* -- Lear, I say, is in quotation marks and small caps. The title of the poem is a quotation - titles formed by indicative independent clauses almost always are ("Tender is the Night"; "A River Runs Through It"; "The Mirror Crack'd," though you'd have to know that not to think "Crack'd" was an adjectival past participle) - so like all quotational titles it's a quasi-motto (epigraph) as well. But it's also a full title; it may be a quotation but it is not an allusion, because the poem is about Roland and the Dark Tower, and not just a quotation from another work. The parenthetical explanation refers us to Edgar's initial-capped Song, which this poem isn't quite meant to replace (it's no song, that's for sure) but to precede. Edgar's song would then be an eerie popular ballad obscurely registering the quest here told more fully, and all the eerier for the obscurity of the recollection.
"LEAR" (Quote LEAR Unquote)* of course refers to the play, but also underscores how a character can become the causal origin of a title. I do not believe that Lear is ever once referred to as "King Lear" in the play that bears his name. He is always just Lear. Putting his name in quotation marks makes it the name of the play; similarly, putting the line that forms the title of the poem in quotation makes makes the quotation marks part of the title and so, conversely, makes the title in turn refer to an actual utterance and not only to the content that utterance declares.
Anyhow, I think that "the ominous tract" which hides the Dark Tower is King Lear itself. If you read that ominous play, that printed tract in which a reader could see Edgar's song (as we're asked to do), you, like everyone else, will find the Dark Tower hidden there. It hides in plain sight, but what is it?
Some mysterious relic of an uncanny minstrelsy.
I think that Browning needed to think about the Dark Tower built of brown stone, just like him (just some human waste), think about what it was and think about its inscrutability. He wanted to assimilate the amazing line to a poem of his own, and yet he didn't want it to lose the strange decontextualized power it has as a stand-alone. So his Roland achieves at the end an ambiguous but final victory in being able to utter the slogan ("slug-horn" is an erroneous typographical creation derived from that perfect word) "Childe Roland to the Dark Tower Came." Its inscrutable ambiguity is its power, and in the last line of the poem Roland and Browning come simultaneously to the place where they can speak the line without denaturing it by turning it the "color of context" (James Merrill).
The line itself is the source and end of Roland's quest. And what is his quest? to make it his source and end. The need to find the Dark Tower is the need not to understand it but to write the poem that will bring you to the Dark Tower, at the end of the line, with all its power intact. Not an easy task to sustain the resonance of that line over dozens of stanzas.
But that's literary need too: trying to sustain the fading coal's transitory brightness, to keep the strange, useless, magnetic pull of literature something powerful, without either understanding it too well or giving it up as a mirage. The need is the need to love the line, which means literary need is the need to love literature. That this is circular doesn't make the need any less powerful and any less real.