I have not done some in a long time, so I will try and share with you what I remember. You do need to find a hard cover book. You should find one with a good binding. Do not get one with glossy pages unless you want to gesso all the pages. Do not get a real old book where the pages are falling apart. You will not have anything that the art will stick to. It is a pain to use gluestick or double sided tape and the page comes off on the tape or glue.
You can use the actual text and picts in the book or you can cover them up. You don't have to pick a theme for your AB but it might help in the beginning so you have something to focus on. Some examples for themes are color, shapes, heads, Zetti, hats, faces, women, dancing, ATCs, houses, doors, portals, flowers, food, stamps, drawings, magazine picts, etc... The list of themes is endless.
The one thing to remember about altered books (ABs) is that there are no rules. You can do whatever you want because it is your AB. You can have a theme or just do whatever. I have had ABs where I just put in new techniques and my experimentations. You can have embellishments, if you want, or they can be flat pages.
There are a lot of different things you can do with ABs. If you have any specific questions, then please comment and include your email so I can answer your directly.
There is a definition of an altered book on the ISABA site: http://alteredbookartists.com/
There are a lot of good altered books Yahoo groups out there if you are serious about altered books and would like to do round robins.
There are some terms common to ABs:
ABs - altered books
tip-in pages - are single pages that you glue into a gutter of a book.
spread - are the two page facing you when you have a book open.
gutter - when you have a spread open, it is the space right in the middle where the page meets the spine (where you glue or sew the signatures into the spine of the book).
spine - when the book is closed, it the the part of the book between the front and back cover where the title and author is a lot. That is the area where the signatures are attached to the covers of the book.
signatures - groups of pages that are glued in or sewn into a book cover
niche - that is a shaped hole that you cut into a book and you put something inside it. It is a big window.
I will put more terms in future posts as they come up or as I think of them.
I think of a couple of artists immediately when I think of ABs:
Beth Cote: http://www.alteredbook.com/gallery/index.html
Corinne Stubson: http://www.glitz-oh.com/
This site loads kinda slow but worth the wait because there are some cool ABs on here:
This site has mondo information for newbie ABers:
Done for now. Will post more later.