I first read this in 1973 and I remember loving it. It's taken the last 30 years to get hold of a copy to read again.
Having re-read it 50 years on, it is certainly a little dated. However the basic premise is still valid. A sort of cross between Kafka's Joseph K and Lindsay Anderson's 'O Lucky Man!'.
An easy read novel it uses a secret dystopian society and economy to consider areas of class, privilege, authority and bureaucracy. Not a great literary work but a fun read with something to say.
Main downside is its portrayal of women; either to provide comfort and sexual favours or as secretaries.