Surface Detail isn't an entry level Culture novel. While newcomers might enjoy this one, you probably need a few Culture books under your belt to get the most out of it (especially if one of the books under your belt is Use of Weapons). As I've mentioned in my review of Matter, I recommend reading the books in publication order, but doing so isn't necessary (the previous link also contains some background on the Culture if you're not familiar with this whole business).
Surface Detail is the longest of the Culture novels and probably one of the most difficult to summarize (it's less convoluted than Excession, though). While this, like most Banks novels, evades attempts to encapsulate the whole plot, I can give a sampler: a "reincarnated" murder victim seeks revenge on her murderer, we are introduced to several new sub-divisions of Special Circumstances, we have plenty of intrigue and galactic politics (this time mostly revolving around virtual reality), there's a heartbreaking story of a separated couple, and the vividly gnarly descriptions of hell realms would make Christians like Dante and Buddhists like Vasubandhu jealous. Surprisingly for a novel this long, I never found it lagging even if I didn't always completely understand what was happening. Have faith, though: Banks wraps everything up.
Speaking of faith, one of the main plot threads revolves around the idea that once it becomes possible to download people's minds into virtual environments, civilizations can create virtual Heavens and Hells (capitalizations from Banks) where the deceased can live on in much the same way as many religious faiths propose. Unsurprisingly, some civilizations use these Hells to threaten and punish people, while others (including the Culture) find this idea deplorable. As Culture aficionados can imagine, this is one of the main conflicts. While the Culture is officially uninvolved in the virtual war set up to settle the dispute between the pro- and anti-Hell factions, they do, of course, end up involved in some way as the lines between the Virtual and the Real are blurred (again, the capitalizations are Banks's; somewhere he says that the official language of the Culture - Marain - contains a phoneme that indicates capitalization).
The Philosophy Report
A big philosophical issue is, of course, personal identity. Would a digital copy of your mind in a virtual Hell realm really be you? I'm inclined to say, "Yes," and so are most of the characters in the book, but readers might draw other conclusions while still enjoying the novel. There are meditations on the difference between the Real and the Virtual, although sadly nothing quite on the scale you'd find in Philip K. Dick (as much as I admire Banks, he maybe missed the chance to do more on this point).
As in Look to Windward, there's the issue of whether living forever (or for a very long time) is desirable, or if the cessation of one's consciousness might be a blessing at some point. Surface Detail adds the issue of whether people need the threat of punishment (whether in a virtual Hell or elsewhere) in order to behave, or if the very idea of hell is simply cruelty by other means. Perhaps more morally evolved civilizations like the Culture would agree to be good just because it's the decent thing to do (with, of course, some outliers to keep things interesting). I have little doubt that some people would jump at the chance to create virtual Hells -- and that others would oppose them. I personally would join the anti-Hell faction. As much fun as it is to imagine hell-scapes, there is rather enough suffering and cruelty in the Real as it is.
That Banks raises such questions while providing his usual quality writing, Big Ideas, and good old fashioned science fiction fun makes this another excellent entry in the Culture series. I only have one Culture book left (The Hydrogen Sonata). This is a sad turn of events, but perhaps Banks teaches us that an end is not always a bad thing.
See also my Goodsreads review.