3) The Wanderer, by Fritz Leiber
The second last of the Hugo-winning novels for me to read, first published in 1964. Set in the very near future (Russians and Americans have manned missions to the moon). A rogue planet appears out of space and starts to dismantle the moon. The resultant high tides and earthquakes cause widespread devastation on Earth.
So far, so pulp. But what I think won Leiber the award is that the story is so well written. A dozen or so different viewpoint characters, some of them rather less prominent than others; a proper sensawunda with regard to the main plot; aliens who actually seem alien; a surprising amount of sex (of course, this was coming into the Swingin Sixties I suppose).
Amused that one character claims to be Guillermo Walker, a direct descendant of the William Walker who took over Nicaragua in the 19th century – there is in fact a real American diplomat of that name and ancestry, but he would still have been a student when this was published.