If there is a gardener’s heaven it must look a lot like the McLean Library at the Pennsylvania Horticulture Society, http://www.pennsylvaniahorticulturalsociety.org/garden/libraryhome.html. Located at 20th and Arch Streets, the library is the perfect place to spend some of the short winter days sampling their great collection of horticultural books and magazines, including practically every new title. You need to have a PHS membership to borrow, but anyone can browse.
The library has a lot of deaccessioned gardening books for sale right now, priced very reasonably. If you’re looking for gifts for gardening geeks, seek no further. You can get a stack of books for cheap while supporting one of the most effective horticultural organizations in the country at the same time.