This is a quick instructable that can be used as a base for many other book based projects.
Some of this will require experimentation to apply to the specific book you are working on, but will give you a great starting point.

BEWARE: This project is not for the feint of heart when it comes to books or history. I am a great respecter of books and it took a bit of courage for me to begin this project, but once I started, it jumped to many other fun projects.

SUPPLIES

Book (hardcover in this case)
- At this point I can only really guarantee how to do this with a loose spine, but with some patience you should be able to unbind any hardcover book.
exacto knife
extra blades
small knitting needle or metal rod

OPTIONAL: microwave or hair dryer

Step 1: Anatomy of a Book

This is a crucial step.
I will be referring to the parts of the book as displayed in the two photos, so take note.

End Papers: These are the decorative pages that are pasted onto the inner part of the cover as well as the opposite side.
Hinge: Inner part of the book where the cover joins the spine and where the book bends/opens from.
Text Block: The pages of the book. These are generally all attached to one main sewn on segment.

Joint: Like the Hinge, but on the outside of the book.
Head & Tail: The head and the tail are the pieces of the cover that extend from the text block.

Step 2: First Cuts

These really are the deepest.

Working from one cover to the next, slice along the seam of the end pages with the exacto knife.

Once you have sliced the end pages apart from each other you should be able to see or feel some strings holding together the text blocks. On one side of the book (i.e front) cut the strings. If you want to save all of the pages be really careful. Otherwise you should be able to easily cut through the strings. On the other side of the book pull out the strings. This will create a nice clean break between the text block and the covers.

Step 3: Separate

This is where it is really convenient if the spine is already separating. If it is already separating then you should be able to simply pull the block out from the cover.

If the spine text block is attached to the spine, then pull out the metal probe. Insert the metal probe between the text block and the spine and slowly peel the two apart. I messed up a couple times and it is really easy to poke through the spine of the book.

Step 4: Splitting Pages

If you have access to a large guillotine then you can simply slice the glue off the text block and have individual pages quickly and easily.
Otherwise, pull out the hairdryer or microwave to melt or warm up the glue.

If you are using a hairdryer slowly move it up and down the glued spine of the text block until the glue becomes soft and you can either wipe or peel it off.

If you are using a microwave be VERY CAREFUL and only use 10 second intervals so that you don't burn the pages.

Once you have removed the glue, slice the threads holding the pages together. In this case the pages are bound together in sets of 10. The cool thing about doing it this way, is that you get to have connected pages like in a newspaper. If you want, you can now slice the pages apart or into whatever configuration you wish.