I want to say something like, "Idoru is the story of love and union in an uncertain world," or "Idoru is an examination of our values in our increasingly mechanized society." However, I don't feel Idoru is about much of anything, except action.
The plot centers around a popular singer (a middle-aged Irish man named Rez) who is bent on marrying a digital Japanese pop idol. The reader follows two unrelated individuals - a contract researcher and a pubescent fan-club member - on separate quests to discover the hows and whys of this improbable union. The researcher has been hired based on his ability to judge the data generated by an individual, and thus understand the course he is on. This ability is the apparent side-effect of clinical experiments in which he participated as a child, growing up in an orphanage. The fan, Chia Pet McKenzie, is an Internet/Virtual Reality addict who gets mixed up in a Russian plot to smuggle nanotech assemblers.
The setting is post-quake Tokyo, in the process of being rapidly rebuilt by nanomachines. Aside from this detail, it is the same Tokyo that exists today - even though the book was written in 1995 and the story takes place in the nonspecified future. Many background details, such as Pachinko parlors and revolving parking garages, are described so abstractly that they would be unrecognizable to the reader who hasn't been to Japan - yet completely uninteresting to the reader who has.
The characters are human and appealing enough, but the story is light at best, and more accurately, flimsy. I got the feeling that revealing details were cut to save space; at any rate, a lot of things were left unexplained. The book is 99% setting, but my "suspension of disbelief" was challenged on nearly every page, with stupidly-coined futuristic vernacular and poorly-written use of English as a second language.
If I have to say anything good about this book, I'll say that it's consistent. It finishes on the same momentum it starts on, maintaining a steady characterization and pace of action throughout. I also enjoyed the scenes in which Colin Laney, the researcher, is faced with a being comprised entirely of data, which really messes with his head.
I also had to admire the Virtual Realities to which the younger characters retire. They don't seem at all remote nor unappealing.
The physics and culture of this story remind me of Neil Stephenson's Snow Crash which was written around the same time. But while Snow Crash explores spirituality, future economies, and the workings of the human mind, Idoru explores only celebrity, and that unsatisfyingly. It was a fast read that failed to distract me, and left me feeling somewhat empty.
And that's all I have to say about that.