Hi Troop, I can recommend lots of Classical books which wonderfully written, I will pour off a list, and will post their link to Amazon, so you can read more about them.
Twisted Truths of Modern Dressage- Philippe Karl
I have a lot of respect for the man, and this book is really enjoyable, some bits are still a bit beyond me, such as the more mathematical side of it, but he illustrates his books and adds some humour, but as well as explaining issues, he also comes up with solutions and ideas to try out, a really good read and one which is good to go back to!
Reflections on Equestrian Art- Nuno Oliveira
Nuno is probably one of my favourite horsemen and I would give my right arm to have been born 10 years before hand to meet him and shake the mans hand, he was a inspiration, his book isn't very big, and thin pages, each subject is about a page long, but it's more thought provoking than a how to manual- it's compact full of his thoughts and I wish he'd actually written a more indepth book about his work and training, that would of been great!
Tug of War- Gerd Heuschmann
This is slightly more off topic and about hyperflexion, correct horse training and a bit about the anatomy and things, it's a good book, and I know Gerd can be a bit silly and rude to people, but I do admire his veterinary aspect of his work, I think it's really good, and this book did teach me quite a lot about todays issues and problems, giving a brief outline and then summarizing, it all in the conclusion, so I'd recommend that too.
Complete Training of Horse & Rider- Alois Podhajsky
I really enjoyed reading this, I haven't finished it totally, but so far from what I've read, it is a cracking book and really insightful to how the SRS trained their horses but has a lot of advice for green/young horses which helped me quite a lot, it has a chapter for Classical Riding- how it works , principles, then a HUGE chapter on the Training of the Horse, and then the Final one is the Training of the Rider. So would try and get that too!
Schooling Exercises In hand- Oliver Hilberger.
I was recommended this book and have wanted it for ages and then found it at a book fair and bought it, it is on Amazon and I really enjoy it, Oliver uses pictures and details to show where to stand, equipment, how to hold the bit, the whip, the cavesson, then exercises, how it benefits the horse, then more advance work such as the Lateral aspect- haven't finished it as I've only had it a week or so, but love it, and something to work through and refer back to.
Enlightened Equitation- Heather Moffett
This is the first book of this kind I read, and I think this has got to be one of the best books I read, what I love about it and Heathers work is how simple and straight forward she puts across her points, without lots of confusing analogies and explanations which just are to much for me, they end up getting confusing, and I just don't register with them, Heathers book talks about the Aids, the Hands, Legs, Seat, then onto more advance stuff, all clearly set out, labelled with diagrams and really thorough and detailed, but like I said, not complicated at all, so I'd most definitely recommend this book if you're to get any of them!!
Books I don't have, but want to get!
Anja Beran- Classical Schooling with the Horse in Mind
School of Horsemanship- Francois Robinchoin la Gueriniere
Workbooks from the Spanish School- Charles Harris
Falling for Fallacies- Jean Claude Racinet
The Great European Schools of Classical Dressage- Alain Lauriox
The Art of Classical Horsemanship- Egon von Neindorff
DVD wise- definitely go for Philippe Karls four part DVD set and Anja Beran's DVD's- they're good
Apart from Classical Books, I'd recommend anything by Kelly Marks and Klaus Ferdinand Hempfling - ( he also has DVD's out!)
Hope this helps