For questions specifically seeking GIS subject matter book recommendations - a separate Book Exchange site has been proposed
This tag is for question seeking GIS subject matter book recommendations. It should only be applied to questions specifically seeking books, be they print or electronic format.
There is currently a proposal for a Book Exchange site which you may wish to follow.
All questions seeking recommendations remain problematic here on GIS SE - see Should questions asking for product, service, data and learning (course, book, website) recommendations be closed?