The problem with book recommendations is that they are either:
a) Too broad and hence not constructive as you'll simply get a list of everyone's favourite book. This doesn't help you as you still have to pick one from the list.
b) Too narrow and hence too localised as the conditions you've set make the situation only applicable to you and, more significantly, only applicable to you at this moment in time.
We have tried to allow some book recommendations but, as you've pointed out, it can lead to inconsistencies where one question is closed but another remains open. Ultimately we may have to review the situation and see if we should allow book recommendations at all.