It has been suggested this question is best addressed as its own question right here in meta. Its been an often enforced bugaboo of moderators to block questions from users seeking reference material on apropos topics. Not always enforced, but too often.
I think the point of the rule OUGHT to be to prevent turning the site into an all-out review source and to prevent overt marketing/sales posts.
I have seen many great responses that were, essentially, a "yes I had that problem too. You should consider 'X'. This book is THE reference for that approach : http://amazon.com/SomeBookURLHere."
Nothing wrong with that. These are often well received comments with a solid number of upvotes (if not THE accepted answer).
So then the issue comes up when I'm looking, for instance, for a book that addresses a particular Parenting issue. This is my community. I don't think its inappropriate to want to come here and ask, "Can anyone recommend some books on toddler behavioral development that they found helpful?" These questions are often very highly viewed and often blocked. That demonstrates a disconnect. It means that we will have to go elsewhere to solve the problems we came here to discuss, with all the peer review and voting and so forth that makes the sites successful.
I'd like to see the rules adjusted to allow a more reasonable approach to community members seeking reference material requests.