One morning it simply happens: after a spectacular display of green shooting stars, the world wakes up to find that all who viewed the previous evening's festivities are blind. What's worse, a weird strain of plant life known as Triffids, harnessed for their valuable nutrients, have begun to get up and walk around, waving their deadly stingers in a decidedly intelligent fashion.
If the premise sounds familiar, it should: The Day of the Triffids was turned into a mildly entertaining schlock film back in 1962 starring Howard Keel. The book takes a more sociological look at the aftermath of a world gone blind. The novel focuses on Bill Masen, an unassuming biologist who wakes up in a hospital bandaged from a previous eye surgery which thankfully left him unable to see the meteor shower, thereby allowing him to still see. From there he moves from settlement to settlement, each one basing its existence upon different fundamentals: strict religious doctrine, modern military dictatorship, solitary fringe reactionaries. His journey, spurred on by his search for Josella, another sighted person he met and fell in love with, propels the story.
The triffids themselves are largely a mystery. They don't serve as the main threat in the book - they are instead the ominous background, the eventual fate of mankind if it does not find some way to settle together peacefully and with purpose. In this regard John Wyndham resembles another science fiction writer, H.G. Welles. A similar set of themes can be found in another Wyndham classic, The Midwich Cuckoos, which was the basis for the excellent VILLAGE OF THE DAMNED.
Granted I'm biased by my love for golden age SF from the 40's to the 60's, but if you enjoy your science fiction with a smattering of philosophy and reality mixed in, then The Day of the Triffids makes for a quick but excellent read.