Books you've found useful in your promotion efforts

[TheShortStack]

Having got to work a bit early this morning, I thought I'd have a wander around the book shop across the road, and was pretty overwhelmed by the sheer number of 'business' and 'marketing' books that were on offer.

So I was hoping that you guys might be able to shed some light on the books you've found useful in your marketing campaigns and which books you'd recommend to other affiliates.

Thanks alot for your help,