If I'm not mistaken, these book synopses are the official synopses used by the publishers. We aim to use as official and accurate information as possible in our database, so we use official synopses when they're available. (Official synopses often contain lots of information about the story.)
Here's more information about these synopses:
The synopsis used in Clifford D. Simak's Way Station is the synopsis of the 1985 SFBC edition.
The synopsis used in M. John Harrison's Light is the official synopsis (Gollancz, 2002).