I will demonstrate how to disassemble a My Book using a new 500gb My Book.
Step 1: Removing the Cover
To remove the cover of the My Book, you will need a flathead screwdriver. I also used razor blades, but they can be replaced or omitted if you would like to do it differently.
First, use a flathead screwdriver to pry the mesh away from the cover (do not try to lift the cover up, you will just break things). Start to pry in the middle of the book and you should see two plastic snaps lift up, I put a razor blade between the snaps to prevent them from locking in again. Do this to both sides.
Second, begin to pry the binding area of the book away from the mesh. Pry in small amounts, alternating from one end to the other. When there is enough of the gap, you will be able to slide the cover off of the mesh with your hands.
Step 2: Remove the Hard Drive
For this step, you will need a phillips screwdriver (any size that can handle the case screws in a computer).
First, remove the plastic led extender (I don't know what this is really called, but it redirects the light to the front of the book).
Second, use your hands to lift up the front of the metal insides. Lift the front up until it is high enough to pull the back out of the mesh.
Third, remove the two screws holding the sata controller in place. Then slide the sata controller down to remove it.
Fourth, remove the four screws holding the hard drive in place and remove the hard drive.
Now the enclosure is fully taken apart. If you decide to put it back together, just follow the steps in the reverse order. There is nothing special you need to know about rebuilding it.