Strong warning: Start with either book 2 (Player of Games) or book...7, Look to Windward.
I strongly suggest you skip book 1 until you're comfortable with the rest of the books that focus on the Culture itself, and not some weird offshoot story that barely involves the Culture.
I also thought about the Minds in the Culture novels. That universe has many gradations of artificial brains.
Though I wouldn't recommend starting with any of the stories in the series. Or reading any at all. Find a summary or a Cliff's Notes instead. Iain M Banks has a talent for making great stories tedious.
Strong warning: Start with either book 2 (Player of Games) or book...7, Look to Windward.
I strongly suggest you skip book 1 until you're comfortable with the rest of the books that focus on the Culture itself, and not some weird offshoot story that barely involves the Culture.