How many times in school have we been told not to go off on a tangent? And subjects such as Math really do not tolerate any digression. Yet Michele Emmer, one of the most appreciated Italian mathematicians, enjoys exploring the side paths: he passionately tells us stories about numbers and people, finds non-Euclidean geometries where we least expect them, talks about dreams and marquetry, algorithms of the gods and happiness of calculus. In this essay, Math follows the principles of pleasure, leaving astounded all those people that were afraid of numbers or considered them too arid.
“Mathematicians’ work can be very concise; they only present the correct results, they do not talk about the doubts, the changes, the errors. They seem like immutable tables of the law, written the way they should be written. When you are narrating, however, you have to know how to tell a story. Being intelligent is not enough”. Here, intelligence and storytelling go hand in hand, wandering freely from prehistory to current events. Along the way they encounter Fields medal winners like Cédric Villani, who recently went from partial derivatives to politics, or the mystic Russian Pavel A. Florenskij, that fought relentlessly for Math not to be reduced to a “dying field”; they witness Luca Pacioli’s memorable “sermon” on Euclide in Venice, in 1508; they pause to observe the first square ever conceived by man, a parietal wall painting inside the Lascaux Cave; they move from cinema to art exhibits. Reading Emmer, we are left with the feeling that the entire living world is built on mathematical codes.

Michele Emmer has taught Mathematics at the Università La Sapienza in Rome. A cinema director, since 1997 he has been organizing yearly conventions on “Math and Culture” – the only ones in Europe. For Bollati Boringhieri he published Visibili Armonie. Arte, cinema, teatro e matematica [Visible Harmonies. Art, Cinema, Theater and Math] (2009, Viareggio Prize for nonfiction) and Numeri Immaginari. Cinema e matematica [Imaginary numbers. Cinema and Math] (2011).

Prologue
1. The creativity of demonstration
2. A memorable sermon / Digression A Inlays, geometries of strange, tiring works
3. In praise of mathematics: philosophy / Digression B Märklin is a train
4. Mathematics and politics / Pavel Florenskij, or mathematics in the time of the Soviets / Maurice Audin / Wolfgang Döblin / A mathematician and presidential candidate in Colombia
5. Playing without the ball
6. The numbers of poetry / Digression C Pasolini screenwriter
7. The Mathematical Man: Robert Musil
8. A Mathematician’s Apology: an autobiography
9. Mathematics? To the theatre!
10. Ars combinatoria: Raymond Queneau / Digression D Mathematical Beauty
11. ‘Even trees and clams can count’ / Digression E Zafiro the bull / Digression F A Ciambra is a film
12. ‘If you aren’t the best, you’re nothing
13. Mathematics never disappoints
14. The genius
15. Figures in the shade
16. An (almost never-ending) story
17. Venetian topologies
18. An exemplary case: Zaha Hadid
19. In the heads of mathematicians
20. Mathematics and art / Digression G Is mathematics masculine?
21. A fantastic event
Provisional epilogue
Bibliography and filmography
Index of names