I'm presently writing my PhD thesis on depictions of animals in modern popular texts, and as a result have read rather a lot of books over the last year or two which fall into this approximate sub-genre, which for want of a better term I'd call 'Animal Quest' novels. Put simply, Horwood's Wolves of Time series blow everything else I've read out of the water. It is very difficult for me to be in any way objective about this book. It had me choked with emotion almost from start to finish.
Unlike many other tales of this sort (not that there is anything else quite like WOT), Journeys to the Heartland is intelligent and multi-layered; metaphorical without being conspicuously or pretentiously so. It's about nature and humanity, religion, and human relations to other species at the turn of the millenium. It has more heart and more guts than just about any other animal fiction I've ever read. You can read it as pure escapist fiction, or you can ponder its deeper significances. Either way, don;t be put off by any negative reviews. My only cautionary word would be that you might wish to avoid this book if you have delicate sensibilities. At times it can be pretty harrowing, and this is even more true of the second volume.
Horwood isn't flattering in his depiction of humanity - The Mennen. In fact I'd guess he's already been accused of being a misanthrope. The point is, the atrocities committed by humanity in the past are offset against the redemption offered in the figure of The Mann - the ex-biologist who crosses the borderline and runs with the wolves. A symbol of hope for the future; though the realisation of this hope does seem to require civil war throughout Europe, leading to the total collapse of civilization :)
Look, I just loved it. I'm sad I'm not still involved in the world of Horwood's wonderful characters (don't, BTW, be put off by the accusations that the book has shallow characterisations. That's nonsense. The characters seem like old companions by the time you've finished it.)
It's a bit hard to find in the USA, but if you're a wolf person, or just like animal stories, you wouldn't want to miss this one. It knocked my socks off.