Long ago, the wizard Redbeard spent his days and nights struggling to achieve fame. Every one of his waking hours was burned in a laboratory or library as he sought to brew some new potion or scribe some new spell. Indeed, he frequently found himself working on two or three dozen projects at a time, rushing from beaker to scroll to flask, struggling to time everything perfectly.
When Redbeard took on Karth Coopersson as an apprentice, the lad assumed he would learn some magic. Unfortunately for him, Redbeard had no interest in teaching, only in achieving recognition, and so he put his new helper to work on a simple project. For Redbeard had found that, often, as one of his projects neared fruition, the excitement would occupy his mind, causing two or three other endeavors to fail simply because they could not hold his attention. To his young ward he assigned the task of preventing this, of coming up with a way for the wizard to easily shift his mind from one task to another.
And so, the boy went to work, studying how the mind worked, and how he could, perhaps, eliminate strain upon it, and eventually, he wrote a book. It was slow progress at first, but as he gathered more information, the book came together more easily, until finally the Tome of Mental Rejuvenation was done. The apprentice presented the book to his ungrateful master and promptly quit, going on to become a tanner in a nearby village. As for Redbeard, while the book proved invaluable to him, he never achieved the fame he craved, and ironically, when he died, the only thing taken by looting adventurers was the Tome - everything else was considered worthless.
The adventurers sold the book to another wizard, Elkarion, who tacked his name onto the title and began to distribute copies to his apprentices and friends. Since then, volumes of the book have occasionally been found throughout the world.
The book has been copied so many times that there is no standard appearance, and the tomes can appear in numerous varieties. They are always, however, thin, for there is not that much writing in them.
What do they do?
The Tome of Mental Rejuvenation contains scores of exercises mentioned in non-sequential fashion. It hops straight from algebra problems to creative exercises to logic puzzles with no real story or connecting monologue. Surprisingly, it is nonetheless a pleasant enough read, as long as one isn’t expecting something deeper.
If the entire Tome is read, from cover to cover, in the order in which it is written, it has an intriguing effect upon the mind, essentially exercising the whole of it in such a way as to minimize the tension in any single portion. it is almost like a massage for the mind.
Essentially, if a mind is focused on one thing, reading this book will allow it to back off from that issue to regain a new, fresh perspective. Similarly, it makes it easier to forget about something which would normally linger on the mind so as to make it easier to move onto a new task. Hence, it could prove useful to someone who has spent too long focused on one problem, to someone whose mind is unable to get over a horrific sight or deed, or simply to someone whose mind is racing sufficiently quickly as to make it difficult to get to sleep.