The 30th anniversary of the release of David Bowie’s glam-rock magnum opus—and the album that defined the genre—is commemorated with this two-disc special edition, released last week. The album proper, should you have not heard by now, is required listening. It’s everything everyone’s ever said it was. Brilliant? Of course. Dazzling? Every moment. From ‘Five Years’ through ‘Rock and Roll Suicide,’ it’s one of the best albums ever released. What it’s really about is anyone’s guess.

This new version has what those who missed out on those last extra-track-loaded Rykodisc reissues have been (not so) patiently awaiting: a second disc of rarities and outtakes. Here are the arguably superior versions of ‘Moonage Daydream’ and ‘Hang on to Yourself’ (recorded under the pseudonym ‘Arnold Corns’). Here are demos of ‘Ziggy Stardust’ and ‘Lady Stardust,’ the former a sparse acoustic arrangement and the latter a hollow, haunting solo piano version. The weird and luscious ‘Velvet Goldmine’ (for any who wondered where, indeed, they got that movie title). ‘Holy Holy,’ one of the best unknown Bowie songs of all time. ‘Amsterdam,’ one of his Jacques Brel covers. Even an Alan Moulder (of Ride and Curve production renown) remix of ‘Moonage Daydream.’

Yes, it’s an expensive reissue. Maybe all that extra razzamatazz isn’t up your alley. But if you don’t own a copy of this album, regardless of whether it’s a 99-cent copy from the vinyl bin or a gold-issue enhanced DVD, you need it. You need it.