The math/physics quickly lost me, but I really love Egan's far-future people and their moral dilemmas about what it means to be human. And the evolution of sex/gender makes me happy. Basically fantastic world-building, less fantastic plot, especially toward the end where things get so utterly weird it's hard to relate to anything. But also that's kind of the point, so. Solid Egan book, not my favorite of his but I still desperately want his vision of the future to come true.

The absolute best thing about this book is the eponymous concept: a way to ensure that, as you grow and change, you are still true to yourself.