It can be called one of music's greatest give-and-take relationships.

The Grateful Dead and Bob Dylan, two acts born out of the 1960s with a musical shelf life that never seems to expire, have shared songs almost regularly since their respective inceptions.

They've even shared the stage, starting in the 1980s when Dylan began hitting the road with the Dead and continuing into the recent tours that have combined him with Phil Lesh and Friends.

More importantly, however, the two now larger-than-life acts have shared a deep appreciation, not only for each other, but also for the roots of rock 'n' roll.

They've always played music grounded firmly in the timeless tradition of American folk, country and blues, but pushed to another level by an individualistic sense of interpretation and a hunger for innovation.

And it is exactly this unique relationship that comes through on the latest attempt to stretch the Dead's commercial capabilities beyond the death of frontman Jerry Garcia.

If nothing else, Postcards of the Hanging: The Grateful Dead Perform the Songs of Bob Dylan offers fans a thoughtful, 13-track, two-disc compilation of the Dead doing exactly what the Dead do best: playing and interpreting music live on stage

Produced by David Gans, and with the help of tape archivist David Lemieux and Dead guitarist Bob Weir, the chosen tracks highlight some great performances taken from shows between 1973 and 1990, although most are from the 1980s range.

A '73 version of "It Takes a Lot to Laugh, It Takes a Train to Cry" features guests Dickey Betts and Butch Trucks of the Allman Brothers Band, and Dylan himself fronts the band on an '87 rendition of "Man of Peace."

Other highlights include a choppy "Desolation Row" from a '90 show, and Garcia's wavering vocals shine on an '81 "It's All Over Now, Baby Blue."

But, regardless of the quality of the tracks, no theme-driven compilation CD can truly capture the real beauty of the Dead's Dylan cover habit. Part of the allure of the songs has always been their placement, a convention that added an appreciated element of surprise and a welcome unpredictability to the Dead's live show. It was always about getting that unexpected "Queen Jane Approximately" all wrapped up in between classic Dead tunes like "Cassidy" and "The Other One."

Postcards of the Hanging is good, however, for those Dylan fans who never really opened themselves up to the loosened live experience of the Dead.

The album gives them a chance to hear how the legendary songwriter's compositions can be expanded by some of the signature, rhythmic guitar playing of Weir and the hypnotic drumming of Mickey Hart and Bill Kreutzmann.

In other words, Postcards of the Hanging offers an auditory snapshot into a vast collection of Dylan covers, but, by any means, it's not to be taken as a definitive anthology. It's a helpful introduction — a carefully chosen taste — that hopefully serves to inspire Dead fans to dip into some other live recordings and uncover a few Dylan-inspired treasures of their own.