RD Laing presented madness as a voyage of discovery that could open out onto a free state of higher consciousness, or hypersanity. But if there is such a thing as hypersanity, then mere sanity is not all it’s cracked up to be, a state of dormancy and dullness with less vital potential even than madness. We could all go mad, in a way we already are, minus the promise. But what if there was another route to hypersanity, one which, compared to madness, was less fearsome, less dangerous, and less damaging? What if, as well as a backdoor way, there was also a royal road strewn with petals and sprayed with perfume? This is a book about thinking, which, astonishingly, is barely taught in formal education. Our culture mostly equates thinking with logical reasoning, and the first few chapters examine logic, reason, their forms, and their flaws, starting with the basics of argumentation. But thinking is also about much more than logical reasoning, and so the book broadens out to examine concepts such as intelligence, knowledge, and truth, and alternative forms of cognition that our culture tends to overlook and underplay, including intuition, emotion, and imagination. If Hypersanity fails to live up to its tall promise, it should at least make you into a better thinker. And so you can approach the book as an opportunity to hone your thinking skills, which, in the end, are going to be far more important to your impact and wellbeing than any facts that you could ever learn. As BF Skinner once put it, ‘Education is what survives when what has been learnt has been forgotten.’