All page references (to U.S. Losses) are to text but the majority of entries require explanation: Axis submarines are keyed to the chronological Appendix by date of destruction or termination of active service, thus pinpointing pertinent data more conveniently than a page number could do. Italics are reserved primarily for ship names, which are U.S. naval units (USS) unless otherwise specified-also conspicuous by parenthetical class designations (called "hull numbers"). . . .
Geographic locations are similarly chain-referenced to basic record of loss. Because of a growing tendency among naval historians, particularly among aficionados of the German undersea fleet in two wars, to introduce a given submarine by commander as well as by number- e.g., "U-47 (Prien)"- and the difficulty of finding this information anywhere in English, it seemed desirable thus to identify further both German and Japanese units by last commander; in a handful of cases no record of or messages from a boat's last patrol appear to exist nor even the name of her captain, nor was this basic information readily available for any of the Italian fleet upon going to press. . . .
Nationalities of foreign vessels will be readily apparent in most instances: Italian submarines, with the exception of a few stragglers from former lettered classes, bear very long or very short names-of distinguished deceased Italians, of minerals or chemical elements. "U" for Unterseeboot is already international (plus 25 former Italian submersibles prefixed "UIT" for U-Boot italienisch). All the larger Japanese submarines had "I" or "RO" numbers, equivalent to "A" and "B" in one intriguing system these people have clung to from ancient times in arranging their syllabics in "i, ro, ha, ni" order-thus a Japanese child recites his "iroha" syllabary just as his Western opposite number learns his "ABC". The "HA"-classes of submarines, of which nearly 200 were on order and perhaps 20 completed by VJ day, are not included in this listing because they were small coastal or transport types and they never saw action. All the various midgets and small submersibles of the Axis trio-e.g., the Seehunde-are also beyond the scope of this small volume; likewise the several I-boats that carried kaitan human torpedos are noted only in passing since this fascinating but intricate sideline has been well covered in recent literature popularly available.
Foreign warships and air fleets bear the following tags:
|HHMS: His Hellenic Majesty's Ship
ORP (Okret Rzeczy Posdolitej): Polish Republic
|HIJMS: His Imperial Japanese Majesty's Ship
|HMAS: His Majesty's Australian Ship
||RAAF: Royal Australian Air Force
|HMCS: His Majesty's Canadian Ship
||RAF: Royal (British) Air Force
|HMIS: His Majesty's Indian Ship
||RCAF: Royal Canadian Air Force
|HMNZS: His Majesty's New Zealand Ship
||RF: Republique Francaise (no true equivalent
|HMS: His (Britannic) Majesty's Ship
||to these labels is used by the French Forces
|HMSAS: His Majesty's South African Ship
|HNMS: Her Netherland Majesty's Ship (HrMs)
||RN (Regia Nave): Royal Ship (Italy)
|HNorMS (or KNM): His Norwegian Majesty's Ship
||RS (Regio Sommergibile): Royal Submarine (Italy)
|L-Lse: Lend-Lease (U.S.-built for Great Britain or France)
||RN (RAN, RCN, etc.): Royal Navy (& Dominion navies)