Norton was one of the first SF authors I read a lot of in my book-laden youth and she remains a firm favourite. Her language is perhaps a little stilted by today's standards, some of her books, this one included, have a distinct lack of strong female characters (although that's probably more the fault of the market she was writing for at the time) and there are definite repeated devices in her work (sapient nonhuman mammals and mysterious abandoned alien cities tend to feature strongly) but she knows how to tell a good story, which is the really important thing.
And who else could weave a dramatic space yarn with an unemployed character getting a temporary job in a pet shop? :-) That's how the hero of this one, Troy Horan, starts the book and it's not long before cleaning out pet cages gets him dragged into an interstellar conspiracy. Splendid stuff.