The Manual of Puissant Skill at Arms is a large enchanted book (it appears in the AD&D Dungeon Master's Guide, but I am expanding that information by quite a bit).
The manual was created in an ancient age by a race of magical warriors. It contains within its dusty pages; the wisdom of a thousand warriors, everything from the proper way to wield a halberd, to advanced martial arts techniques that only a true master could ever use.
The creators of the books knew that simply reading a book did very little, so they infused their books with power. Each page will appear in just the right language, and will speak to the reader in a style reserved just for them. (Two different men could read two copies of this book, and every word could be different, depending on what they needed to hear). Each page vanishes as it is turned, within minutes the reader will not even remember what was on that particular page, the knowledge will bury itself deep within their mind, as if they knew it all along. After finishing the book, the reader will have been permanently blessed with a lifelong increase in his martial abilities, as if he had trained for many years longer than he truly had. Within a few weeks the reader will have completely forgotten about the book altogether (and the remains of the book will have vanished), but the effects of it will remain forever.
This book is dangerous to those who posess the skills of a wizard. Even reading a single page will leave them dumbfounded and cause them to forget years of their magical training (and life). Holy men and rogues will not be able to understand the writing within the book, but normal men of no skill can receive full benefits (becoming a trained warrior in a very short amount of time).
Now for the AD&D game terms for all this. Fighters gain 1 level upon reading this book. Wizards lose 10,000 - 60,000 XP for even looking at a single page. No one else is affected by it.
This is only my interpretation of this item, which is based largely upon its use in the older versions of the Dungeons & Dragons series of games. Your Manual of Puissant Skill at Arms may be totally different, so always be sure and read the instructions.
| 
