Just an fyi, there are no Hedychium specific books. On gingers there is my book (general info), Gingers of Peninsular Malaysia and Singapore, some works on edible ginger, and a few other projects are in the works but I don't know when anything will hit the shelves.

Tom Wood is doing a monograph on Hedychium, and might turn it into a book for the general public as well, though I imagine that project is in the future.

Tim Chapman