Acknowledgements

Threshold is for Karen Brooks as part thanks for being such a dear friend during one of the very best and very worst years of my life.

Thanks and acknowledgements also go to Rodney Blackhirst for his enthusiastic exposition of the One (and for those fascinating bodily fractions), Terry Mills for his interesting association of infinity with a Big Mac, Cliff Carrington for his knowledge of the pyramids, and Roger Sworder for an illuminating (and refreshingly frank) discussion of the nuptial number. It was fun, guys, but I bet you wish now you’d never let me in the front door.

And with deepest apologies to Pythagorus, Plato, Euclid…