Consider that the book and the force applied by the hand is all together one part, so no worries if there is any slippage between the hand and the book. So then, the book is pressed against the wall with some force. The free-body diagram drawn in my head has a force of friction( μ static*normal force), a horizontal normal force, force acted on the book by the gravity, W=m*g. Then I also have a force applied at some angle. So my first question is does the x-component of the Force applied be the same as the force of normal. If that is correct, then wouldn't the angle from the wall where it is impossible to hold onto the book is when the Force of normal, or x-component of the force applied is less than or equal to zero. But then, that doesn't right, I'm guessing there is something to do with the force of friction. So is my thought process right or wrong?