Here’s the part in the prologue that explains what the title means:
A phrase pops into his head from out of nowhere. “Everybody . . . all of them . . . it’s back to blood! Religion is dying . . . but everybody still has to believe in something. It would be intolerable – you couldn’t stand it – to finally have to say to yourself, ‘Why keep pretending? I’m nothing but a random atom inside a supercollider known as the universe.’ But believing in by definition means blindly, irrationally, doesn’t it. So, my people, that leaves only our blood, the bloodlines that course through our very bodies, to unite us. ‘La Raza!‘ as the Puerto Ricans cry out. ‘The Race!‘ cries the whole world. All people, all people everywhere, have but one last thing on their minds – Back to blood!” All people, everywhere, you have no choice but – Back to blood!
Maybe the last half of the book will be about a bunch of middle-aged white Economics professors from an nice exurban university that visit Miami for a conference and enjoy chalupas available at low, low prices . . . but I doubt it.