Van Morrison has always been a prolific artist, releasing nearly an album a year for 30 years.

All the while, he had a stockpile of unreleased material in the vaults, much of which became legendary among collectors.

A selection of this material was planned for inclusion in a box set, but when he realized the sheer amount of worthy material, he decided to separate the unreleased cuts and release them as the double-disc set The Philosopher's Stone.

Certainly, the collection is for fans, but not just hardcore fans -- there are a number of great songs here, from "Madame Joy" and "Naked in the Jungle" to "Crazy Jane on God" and "The Street Only Knew Your Name." A full 25 of the 30 tracks on the album have never been released in any form, while the remaining five -- "Wonderful Remark," "Real Real Gone," "Flamingoes Fly," "The Street Only Knew Your Name," and "Bright Side of the Road" -- are present in alternate takes.

In all, The Philosopher's Stone is a welcome addition to Van Morrison's official catalog -- some of these songs are so good, it would have been a shame if they had stayed locked in the vaults.