PAPERBACK. Paper edition. 64pp+74pp+74pp+95pp, b/w illustrations, staplebound octavo paperback. vol.1: Aeromarine - Christofferson, vol.2:Curtiss D,E,F,G and Armored Tractor, vol.3: Curtiess J,N, JN-2, JN-3 and N-8, vol.4 Curtis JN-4, JN-4B, JN-4C, R-s, R-4, and Twin JN isbn vol.4: 0912792108. slight cover wear, single ink mark to rear cover vol.1 otherwise very good-.