DS was like this (or, actually worse) from around 18-22 months. Then it suddenly got better.
How has he been in the past? DS always fought sleep untill roughly 22 months when all of a sudden he started to relax about going to bed. Then finally things improved - we had been spending 2+ hours getting him to sleep and his bed time was getting later and later... It's still a bit hit and miss but much better now.
We didn't actually do anything differently, he just got over it, or something.
You could try starting bedtime earlier, but it sounds like you've done that and it doesn't work. I wouldnt' worry about the books so much, you know best what does and doesn't work anyway.