Sleep books?

My son at nearly 10 months is still a really bad sleeper! I have tried everything ( except letting him cry...... which I will NEVER do ). He cries and fusses for up to 2 hours sometimes with me walking in and out of his room to comfort him, but then will only sleep for 30 mins. One day he only had 25 mins for the whole day but then is so exhausted he goes to bed at 6.15pm. He wakes between 2-8 times a night.
I have the books, no cry sleep solution, sleeping like a baby, save our sleep and the science of parenting, but I was looking for a book that goes a bit deeper into sleep issues and problems.
Does anyone know of any good books that may help me and my little boy?

Anything in here: BellyBelly Pty Ltd - Baby & Parenting

Namely Pinky McKay's books and 'The Science of Parenting'

I know its not what you are looking for, but would you try Ngala for a day visit? We went there a few months ago and said NO c/c and they said whatever you want, we will do. So we had a day stay which helped the problem at the time- it just opened our eyes to what we were doing to prevent baby sleeping as well as she could (which has never been great). Not saying that you or any parents are to blame, just that some actions we take can help and some hinder. In saying that our 8 month old goes from 8am to 6pm some days (about every 4) without any day sleeps. Other days it's half an hour once or twice in the day. 6pm is now her bedtime. I have read the books you mentioned plus numerous others that were not helpful enough to mention.

I have heard Ngala is really good, like Deirdre said, you could try a day visit. Otherwise they have a great book called "Secrets of Good Sleepers"