There isnt really an appropriate way to begin this review other than to say that this is, for me, Ballard's best and that he has clearly only improved with age. Millennium People could not be more typical Ballard from the outset: Urban setting, usual themes, dystopian vision etc. but he has excelled himself by sticking to his strengths and improving on them.
Characters in Millennium People are far more sophisticated than a Ballard reader might expect. From the mysterious Richard Gould to the fiery Kay Churchill this improvement in characterisation helps convey the many messages in the story. What Messages? Well as usual, themes are around society, psychology, philosophy and politics, but instead of being deduced from the outcomes of the plot (as you might with say, High Rise), the morals come directly from the characters mouth and being the ever naive and passive David Markham, you get to hear everyone's side of the story.
The development around middle-class society, violence and even the meaning of life is very well handled and kept interesting and relevant with a twisting, mystery plot to which you're always trying to guess the ending whilst grappling with the challenging questions the characters ask of you and Markham.
To summarise, this is exciting, accesible, thoughful, sophisticated, interesting and enjoyable. It has the feel of an author reaching perfection with the complexity of The Atrocity Exhibition combined the atmosphere of High Rise...
...and to top all of that, this edition from the nice people at Harper-Perennial comes with a lovely jacket and an interview thingy at the end so read it and enjoy!