My favorites, in no particular order.
Fountain Pens: United States of American and United Kingdon by Lambrou
Dunhill-Namiki and Lacquer Pens: Maki-e Pens Guidebook by Murakami
Fountain Pens of the World by Lambrou
Fountain Pens and Pencils : The Golden Age of Writing Instruments by Fischler and Schneider
Fountain Pens: History and Design by Giorgio Dragoni
This ought to get you started! [8D]