The most interesting aspect of The Sandman: Overture is the paradox of the title. As this story is set immediately before the start of The Sandman, it would seem a fitting name as an overture is "an introduction to something more substantial." But this story is just as substantial as Neil Gaiman's earlier series. And as far as introductions go, readers who have yet to discover The Sandman (presumably there are still some out there somewhere in The Dreaming) would be better served to get to know the original series before introducing themselves to Overture.
As The Sandman: Overture #4 opens, we find Dream of the Endless continuing his journey to save all of reality. Accompanied only by a lost child and another aspect of himself in his guise of the Lord Of The Dreams of Cats, Dream must travel far and further still. He will seek the wisdom of his father and journey to the legendary City of Stars. While this story is interesting as an abstract tale, it will mean far more to those readers well familiar with the story of The Sandman who will know the significance of The City of Stars or why Dream recalls the tale of the first time he had to kill in the line of his duty.
The artwork by J. H. Williams III is as wondrous as one would expect the artwork for any chapter of The Sandman to be. Indeed, I fear I do Williams' contribution to this collaboration a disservice with my choice of scans to share. The best bits of the artwork involve intricate two-page spreads that my scanner could not manage. And a composite image would fail to capture the scale and grandeur of the artwork. So please believe me when I say that Williams' art matches Gaiman's script in eloquence and splendor.