Tom Waits grew steadily less prolific after redefining himself as a junkyard noise poet with Swordfishtrombones, but the five-year wait between The Black Rider and 1999's Mule Variations was the longest yet.

Given the fact that Waits decided to abandon major labels for the California indie Epitaph, Mule Variations would seem like a golden opportunity to redefine himself and begin a new phase of his career.

However, it plays like a revue of highlights from every album he's made since Swordfishtrombones.

Of course, that's hardly a criticism; the album uses the ragged cacophony of Bone Machine as a starting point, and proceeds to bring in the songwriterly aspects of Rain Dogs, along with its affection for backstreet and backwoods blues, plus a hint of the beatnik qualities of Swordfish.

So Mule Variations delivers what fans want, in terms of both songs and sonics.

But that also explains why it sounds terrific on initial spins, only to reveal itself as slightly dissatisfying with subsequent plays.

All of Waits' Island records felt like fully conceived albums with genuine themes.

Mule Variations, in contrast, is a collection of moments, and while each of those moments is very good (some even bordering on excellent), ultimately the whole doesn't equal the sum of its parts.

While that may seem like nitpicking, some may have wanted a masterpiece after five years, and Mule Variations falls short of that mark.

Nevertheless, this is a hell of a record by any other standard.

Waits is still writing terrific songs and matching them with wildly evocative productions; furthermore, it's his lightest record in years -- it's actually fun to listen to, even with a murder ballad here and a psycho blues there.

In that sense, it's a unique item in his post-Swordfish catalog, and that may make up for it not being the masterpiece it seemed like it could have been.