He believes that, like Pompeii, the ship will eventually become ''a dig'' simply because it's there and no one's policing it. Lord describes the failed search parties that have looked for the ship since it sank, and the successful one. In any event, video pictures 73 years later show that the whole stem is missing. Witnesses, including experts, were at odds whether the ship broke up while sinking some may have been misled by a falling stack. Also, it's very unlikely that the band was playing the solemn ''Near, My God, to Thee'' as the ship went down evidence now shows that a popular London air heard at skating rinks, ''Song d'Automne,'' was being played from memory. class women and children were saved, but only 42% of those in third class. Despite White Star's contention that there was no class distinction in use of the ship's scant number of lifeboats, 94% of first and second. Ironically, if the ship had struck the berg headon, rather than at the glancing blow that gashed the bow underwater, the compartments would have kept it afloat. The compartments weren't watertight at all, rising only 10 feet above the waterline and having no ceilings: as the boat sank, water simply slopped over the partition tops from one compartment to the next ''until the ship had to sink.'' And speeding through haze in subfreezing waters indicative of icebergs, the wonder is that the ship didn't strike one earlier. The ship's supposedly watertight compartments led to this error.

But Lord quotes a company vice-president who was still calling the ship ''unsinkable'' some hours after it had actually sunk.

Among the myths punctured: that the Titanic never was called ''unsinkable'' by the White Star Line. The Lord style is still clear, uncluttered, and utterly readable (his Incredible Victory is a classic on WW II), but he simply has less to work on here. What with his vast hindsight and the recent discovery of the sunken liner, this is likely to be widely read. Thirty years after his classic A Night To Remember, Lord offers a companion volume that sifts anew the truth from the myths and legends surrounding the sinking of the Titanic.

The Night Lives On by Walter Lord