Dishonest or ‘crooked’ arguments are nothing new, but recently our fractious politics coupled with the invention of the Internet have lent them a fresh intensity, and a wider reach. Would that Straight and Crooked Thinking, written by Robert H. Thouless and first published in 1930, was now more widely read and taught in schools. This little book would not solve all our problems, of course, but it might help us see through partisan propaganda, take on unprincipled Internet warriors, persuade others honourably, defend our own beliefs effectively and (crucially) change our minds when necessary.