Williams's previous release, 1998's masterwork Car Wheels on a Gravel Road, was as vivid as its title. You could feel the grit ground into Car Wheels' treads as clearly as you could hear the busted-heart melancholy in Williams's voice. Essence, by contrast, is more of an abstraction. Emotions are vaguely expressed, the imagery less rich and varied. Where the earlier album's songs were full of place names and references that served as signposts to Williams's emotional state, this much more passive journey maps a mood: Spare the evocative details and spoil the impact. Even so, Essence has its moments, most of them wafting on an abundance of lovely if languorous melodies. Williams is at her best here on soft but poignant tunes like "Bus to Baton Rouge" and "Broken Butterflies," the piece that ends the album. It does so on a clear, promising note that will leave fans hoping her next offering won't, as Car Wheels did, require six years in the shop.