The Joy Of X: A Guided Tour of Math, from One to Infinity

by Steven H. Strogatz

In that sense, math always involves both invention and discovery: we invent the concepts but discover their consequences.

the primitive logic of “the enemy of my enemy,” and this part is captured perfectly by the multiplication of negative numbers.

Maybe we’re wired to doubt the commutative law because in daily life, it usually matters what you do first.

Calculus is the mathematics of change. It describes everything from the spread of epidemics to the zigs and zags of a well-thrown curveball. The subject is gargantuan—and so are its textbooks. Many exceed a thousand pages and work nicely as doorstops.