Night Fishing for Trout, by Jim Bashline
Pennsylvania Trout & Salmon Fishing Guide, by Mike Sajna
TU Guide to Pennsylvania Limestone Streams, by A. Joseph Armstrong
If you want an encyclopedic work:
Fishes of Pennsylvania, by Edwin Cooper
American Shad in the Susquehanna River Basin, A Three-Hundred Year History, by Richard Gerstell
Penn's Creek (River Journal), by Daniel Shields
Fly Fishing Pennsylvania's Spring Creek, by Daniel Shields
Pennsylvania Report of the State Commissioners of Fisheries (late 19th century publications) are interesting reads
Juniata, River of Sorrows, by Dennis McIlnay
Not as much angling but a history of the waterway:
Susquehanna, River of Dreams, by Susan Stranahan
Down the Susquehanna to the Chesapeake, by Jack Brubaker
Rivers of Pennsylvania, by Tim Palmer