For many, it was an introduction to a voice that, at first blush, seemed to be a strange brew with the hard-living wail of Plant, but combined in surprising ways to create a truly outstanding album. I only knew of her via the O Brother, Where Art Thou? and Cold Mountain soundtracks, both influential in the resurgence of bluegrass. But Robert Plant? Colour me intrigued.

A packaged collection of hits is therefore a timely way to expand the knowledge of curious converts like myself. The disc meanders, in no particular order, through Krauss's impressive discography, which covers styles ranging from bluegrass and country & western to what can only be described, for lack of a better description, as adult contemporary. I must admit, though, I didn't find too much of the murky blues and heartbreaking country that I liked so much on Raising Sand. Instead, I found a singer whose music seems sanitized and safe by the measure of folk music’s darker side. It’s an image more in keeping with the one that has obviously been created for her post-Grammy success – an elegantly coiffed and airbrushed cover pitches her squarely at an adult-contemporary crowd.

Tracks like the opener, "Simple Love", while immaculately executed, are just too clinically produced to make me care much about the subject or the singer. As the album progresses, however, I found the songs more satisfying - "So Long, So Wrong" slips some of the raw thrill of country into the jangling banjo and fiddle, and is the high water mark of the album. "Empty Hearts" weaves melancholy slide guitar between the sheets of Krauss’s quiet, plaintive voice, mining the same terrain as Norah Jones, while the plaintively sweet version of "When You Say Nothing At All" has a lot going for it.

The "essential" moniker is accurate in that it provides a broad palette of Krauss's work – and there's likely to be something to please anyone with taste that ranges along the folk-country scale. Krauss's die-hard fans will, I'm sure, be delighted with the selection. The downside, however, is that there's not a whole lot of cohesion to the album. For a relative newcomer to her music, though, I got enough of a taste of her work to want to investigate her back catalogue more thoroughly. On that basis alone, you can consider this album a success.