The world of tiers Book

This is an Omnibus volume of the first 3 books. I read these long ago and really had almost forgotten them. When Robert Wolff finds a horn that opens a gate into what is apparently another universe (and steps through, don't they always? But then if he hadn't we wouldn't have a book to read would we?). He finds himself on a world made up of ascending "Tiers", much like one disc atop another (No, Terry Pratchett had nothing to do with it).

We get a "revelation about Wolff as the first volume ends (though I'd be surprised if the revelation surprises you) and then we move on. The first book bases a lot of the creatures and so on on varied religious traditions and the second volume (Volume 1 The Maker of Universes, Volume 2 The Gates of Creation, volume 3 A Private Cosmos) seems to lean heavily on the poetry of William Blake (religious poetry). Without spoilers I'll just say there is action and constructed worlds to adventure in here also.

The third volume is okay but not as good as the others in some ways. lots of action, but, well there is a point when you almost need a program to know who is who...no more or it'll again be a spoiler.

As I said I read these a long time ago (this is not the edition I read and I no longer own them) and was tempted to go the three star route, but decided that the enjoyment factor outweighed any slight... predictability etc.