As the author's ostensibly first try at science fiction, this book was ok. There are flashes of the awe-inducing imagery and conceptualization that appear in his later Culture books. But the story of Horza, the Changer (or what would be known as a shapeshifter in sff circles,) is much too meandering and ultimately predictable to make this book standout among the others of the same genre and publication era. In some instances, Banks tended towards shock value in depicting graphic scenes of torture and mutilation, when more mileage may have been had from introducing more gosh-wow sf wonders. The unlikely sequence in the tunnels at the end of the book was more mundane than the first part of the book.
[b:Consider Phlebas|8935689|Consider Phlebas (Culture, #1)|Iain M. Banks|http://d.gr-assets.com/books/1327951890s/8935689.jpg|14366] is most notable for the initial exposition of the Culture, a concept for universal order that provides the backdrop for many later Banks sf novels. The Culture is ruled by the Minds, machine intelligences that seem more than just AIs since they employ AIs for day-to-day tasks such as planetary surveillance. Humans in the Culture live as pampered children, freed from the present-day pursuit of wealth, health, and the higher virtues, and given to frivolities such as games of chance, wild risk-taking, artistic endeavors and hedonism. In [b:Consider Phlebas|8935689|Consider Phlebas (Culture, #1)|Iain M. Banks|http://d.gr-assets.com/books/1327951890s/8935689.jpg|14366], the Culture is nascent and in the midst of a space-spanning war with the Idirans, religious fanatics on a pogrom to conquer and convert worlds and planets to their vision of faith.
On this parchment, Banks crafts a dark tale of spies --- one, Horza, working for the Idirans, another, Balveda, serving the Culture --- both in pursuit of a Mind gone awol in a desolate back planet. Horza and Balveda engage in a running debate on which of the two parties to the war is deserving of victory. But the final arguments are made through the events of the story
From the purely entertainment aspect of the book, I rate this 3 stars.