It is highly likely you are referring to one of his popular works on mental ability, IQ, or general intelligence, often titled along the lines of or "General Mental Ability" . These books are considered the "gold standard" for training the mind to think logically and analytically.
He devoured the book. Chapter Three: explained why he kept losing his keys. “Your brain is not a hard drive. It is a spiderweb. Do not store memories; dance with them.” He started using Thorpe’s "emotional tagging" method—attaching a ridiculous color to every task. Red for urgent, purple for "ignore, it's anxiety." Within a week, his 3 a.m. panic sessions stopped. It is highly likely you are referring to