This book is about a reporter, Joshua, who watched once the US championship on memory. Joshua was at first surprised that some people spent a lot of time to compete in a rather useless challenges (e.g. remember a long string of random digits). He also had the assumption that those “mental athletes” (MA) were gifted intellectuals, naturally better than the normal population.
Joshua then made friends with European MAs (apparently the European memory scene, especially Germany and UK is much better than the US). Those guys taught him the tricks to remember, as it was all tricks, no need to be a genius: and voilà! Joshua, after an intensive year of training, became the US champion of memory.
The memory tricks are quite different from the spaced repetition I’m used to (e.g. Anki). Joshua used mainly the Memory Palace for remembering facts and playing cards order. The goal is to associate items to remember to funny situations, ideally with a “People doing an Action on an Object” (PAO). Each situation will be placed in an imaginary location. To recall, you have to – still in your head – walk through all locations and find the desired item.