The most comprehensive book I have seen on aquatic plants. It is really two books in one: Part One covers pond building; submerged, floating and marginal plants; water features; fish; and pond maintenance and repair.
Part Two covers water lilies (hardy and tropical); lotuses;
and other smaller genera ie Nuphar, Victoria, Euryale, Barclaya, and Ondinea.
I interlibrary loaned in many books on water lilies and water gardening....this one, though out-of-print, was the only one I *had* to purchase.