This thread could be useful even if the Springer action was a mistake (or whatever) and the free books download facility has been withdrawn - because many people have mentioned book titles that they like. I, for one, was not aware of many of these titles, and my guess is that many others would be in the same position. So this thread is a useful resource. It would be great if readers who can, could vote this thread up for a day or two at least, so it stays visible until people get a bit of time to copy book titles to check out or buy later. Thanks.