The problem with the analogy of it being like a book comes up here.
With a book, once you read the information it is stored in your brain. You can re-access it and study it further, but if your memory is good enough you could remember and use the information for the rest of your life.
The memory stones, on the other hand, do not do this. When you enchant a memory stone, the stone stores the information required to cast the spells. When you activate the stone, however, it does not transfer this knowledge to you.
The knowledge remains on the stone, all you have is the knowledge of how to activate the stone. The stone requires any materials that are consumed still, such as Heat or VE, and you pay those costs, but the stone is what performs the spell, not you.
Think of it like an automated manufacturing line making say, a shoe. Assuming the factory line was made by a single person for simplification reasons, the person who made the manufacturing line would also need to know how to make a shoe, otherwise the manufacturing line would not work correctly. You on the other hand, as the operator, do not need to know how to make a shoe. You only need to know what materials the machine needs, and what buttons to push to make the machines do the work for you.