This is one of Clarke's earlier and perhaps not so well-known science fiction novels. It's based on an intriguing idea that was, before the first landing on the moon in the 1960s, perceived as an actual possibility: that some lunar plains, because they appeared to be exceedingly flat and smooth, were composed of extremely fine dust. Such a "sea of dust" would be far more treacherous than any quicksand on Earth, and there was a very real fear that the first lunar probes would sink and instantly vanish into such a sea. Clarke wrote A Fall of Moondust between August and November 1960, and it wasn't until the mid-1960s, when the Luniks and the Surveyors landed on the Moon, that it was proved there were no dust seas there. Clarke had already used the idea of "moondust" in Earthlight (1955), but the original concept was first developed by James Blish, in one of his science fiction stories (as Clarke relates it in the preface to the 1987 edition of A Fall of Moondust).
The story is a psychological thriller in a science fiction setting on the Moon. Captain Pat Harris, "the skipper of the only boat on the Moon," is the pilot of the Selene, which is a dust-cruiser (the only one) on the Sea of Thirst. The Sea of Thirst is composed of moondust, and the Selene is basically a pleasure cruiser for wealthy tourists. Captain Harris, together with the stewardess Sue Wilkins (an attractive and capable young women who is the object of Harris's erotic fantasies), takes the passengers on a cruise across the sea to the Mountains of Inaccessibility and back. But on the way back, disaster strikes (when a huge gas bubble bursts under the surface), and the Selene begins to sink into the dust.
The rest of the book switches back and forth between the rescue efforts, under the command of Chief Engineer Lawrence, assisted by the arrogant and anti-social Dr. Tom Lawson from the observatory at the Lagrange II relay satellite, and the efforts made by the crew and passengers of the Selene to stay calm and occupy themselves until help arrives (and to stave off every new disaster that occurs, regular as clockwork). Also involved in the events, as an outside observer, is the news reporter Maurice Spenser of Interplanet News. Among the passengers in the sunken cruiser is the famous Commodore Hansteen, the Commodore of Space who "had led the first expedition to Pluto, who had probably landed on more virgin planets and moons than any explorer in history," and he quickly assumes a leadership position. Captain Harris, after a pep talk from the attractive Sue, realizes that since he's the captain, he must act like one (but there is never any friction with the Commodore, since people in Clarke's stories are usually far more reasonable and civilized than real people would ever be), and for this he is rewarded with the sexual favours of the desirable young stewardess.
One thing I thought was a little strange was how Commodore Hansteen, within minutes after the disaster had occurred, immediately began thinking about and planning how to occupy the passengers so that they wouldn't panic during the long wait until the rescue efforts began. I don't think that's how anyone would have reacted in a situation like that. The first impulse should have been to try by any means available to get out of there, and it would not have been until later, at the first signs of stress among the passengers and when it was clear beyond any doubt that they were all in for a long wait, that the time would have come for worrying about the passengers.
A Fall of Moondust is an interesting and pleasant read, and the outdated moondust idea actually gives the story a "Buck Rogers" kind of feel (I'm sure Clarke would be insulted at a suggestion like that). On the other hand, the story is, as always with Clarke, strictly scientific in all details, and it's quite interesting to see how the rescue efforts proceed. Recommended.