To respond to stiknrudas post, the unusual attitude recoveries are generally done quite near to the start of the course because then your instructor can send you off to do solo practice of the basic manouevers (loops, aileron rolls etc) secure in the knowledge that you can get yourself out of trouble. If you think about it before any solo aeros a good revision of, or often nowdays an introduction to spinning is essential. You should also be familiar with recoveries from the vertical and inverted before attempting even a solo loop, because if you get it wrong then that is where you're likely to end up.
Its also important that your instructor knows exactly what you want to achieve. When I was current at teaching aeros years ago I used to make sure that the student knew what they were getting. If they wanted to do the AOPA syllabus for fun then fine, but if they were interested in competitions then right from the start I would send them off to someone who flew comps. OK it might have lost the flying club a few customers but at least I didn't feel I was ripping anyone off.
Regarding books I did everything upto the aerobatic Instructor course with Ron Cambell and Barry Tempests' basic aerobatic book in the AOPA series (don't know if its still in print). The others are all interesting but all you really need initially is a basic manual, the aircraft POH and plenty of good long briefings from an instructor who knows your aircraft.
Finally remember it's all about practice, and don't be ashamed to stop if you feel uncomfortable. Most people get a bit queasy sitting through someone elses aeros, hence as was mentioned above short training flights are better.