The novels are well written, don't read as being too out of date and in fact have some quite remarkable plots. It's a bit of a period piece in places, but they are always fast-paced and entertaining. A bit like traditional SF novels, not literature, but capable of being a bit above average for pulp fiction.
Gardner is well out of fashion since his peak around the TV series starring Raymond Burr, but still well worth becoming aquainted with.
