Posted this in a separate thread, and haven't seen anybody else mention this, (and search turned up nothing) but it's a fairly serious bug in training, and deserves it's own post.
NOTE: I've only checked in 1.44
Training a skill (or reading a skill book) sets the max amount you can learn that skill to whatever level the trainer/book gives. EVEN IF YOUR MAXIMUM IS ALREADY HIGHER. So if you have the imp train you to level 10 pickpocketing, not only does the BF trainer still give you the option to train to lvl 6 pickpocketing, but if you choose that option, you can then only learn up to lvl 6. Your max gets REDUCED. And as near as I can tell, the same happens with books. The medical officer can give you a book that trains various skills (including individual healing) up to lvl 5. If you have already trained up to lvl 6 at the battlefield trainer, the book REDUCES your skill max to 5.... and since you've already trained to lvl 6 from the battlefield trainer, he no longer give you the option to train up to 6. Until you find a new trainer, you're stuck at 5.
So, before choosing to train a skill from somebody, make sure the training will actually IMPROVE your maximum, and not reduce it. Similarly, before reading a skill book, save, try the skillbook, see what skills it increases and check to see by how much, then load, and make sure using the skill book was an improvement. If it wasn't, then ditch the book somewhere, and never use it.