I admire altered artworks, especially some of the wonderful things I've seen made from old and unwanted books. Artists who recycle existing materials to make new things have great vision and ingenuity, and the green aspect of their work appeals to me. Go to any thrift store or flea market and you see so many books that are outdated or damaged, or simply something no one wants to read again. To find a new use for these books saves them from ending up in the trash.
That said, I have a bit of a problem personally ripping up books, even with the goal of making something new. I've tried -- once -- while making an altered art journal out of an unwanted hardcover, and it was oddly very distressing. I had to tear out half the pages to make room between the covers for my alterations, and I didn't like it at all. To begin with books are sacred objects to me, and I also felt as if I were yanking pieces off another author. After that book I gave up on altered book projects for quite awhile.
I do frequently pick up old books to read, and I found one biography a couple months ago that seemed interesting but turned out to be a huge dud. The story actually offended me on a couple of levels, and I seriously considered tossing it in the trash. Then I had an odd thought: if I were Torian, I couldn't throw away the book -- in my universe, it happens to be illegal (part of how the British Empire controls what Torians read.) So what would a Torian do with a book they despised and didn't want anyone else to read without breaking the law?
The British once famously tried to make the kilt illegal (I believe it was the Dress Act of 1746), and -- at least according to one old Barbara Cartland novel I read as a teen -- Scottish men attempted to dodge it by pinning pants to the back of their shirts while still wearing their kilts. Whether that was based on fact or just fun fiction, it's the sort of lawful defiance that helped me decide what to do with the books being forced on Torians: they'd keep them intact but make sure no one could read them by the same sort of scheme.
I tested several methods of surface alteration before I settled on watercoloring the pages. For this I used two types of watercolor paints: a very inexpensive one by Simply Art, and some of my Luminarte metallic watercolors from an art class I took last year. The only other supplies you need for this project are an unwanted hardcover book, paint brushes of various sizes, water, a small spray bottle filled with water, wax paper or pieces of laminated cardboard (to place under the pages you're painting), a protective surface to work on (I used an old plastic placemat) and materials like bubble wrap, tulle or other textured materials to press on top of the painted page to make impressions as it dries (optional). Also, when you choose the hardcover book you want to alter, pick one with strong pages and signatures that are sewn, not glued, to the spine as this has a better chance of staying together and intact during the painting process.
Beginning from inside the front cover, place your wax paper or laminated cardboard under the right hand page. Lightly spray the surfaces of both pages with your water bottle or brush with plain water to dampen them (this also helps prep the page to receive the paint and keeps the paper from curling.) Begin to paint, covering both pages with your watercolors. You can use a single shade or more than one; I began on my journal with a dark violet and a bright peachy orange and let the colors mingle on the surface of the paper (I use plenty of water to dilute the paints when I want them to blend together, too.) Paint around any words you want to leave intact to be plainly seen in your finished journal. When you've covered both pages, set the book aside and let it dry completely -- and this is an important step that will help prevent your painted pages from sticking together.
When your pages are dry, place a piece of wax paper or laminated cardboard between them and flip to the next pages, and repeat your painting and drying process. To make texture impressions on your pages, once you've finish painting press a piece of bubble wrap, net tulle, lace or other textured material over the paint and let it dry with the material in place. When you remove it, your watercolored page should show impressions from the textured material.
Here's a slideshow of some of the pages from the journal:
Some tips to prevent problems: try to keep mopping up water that may collect in the seam between the pages you're painting to prevent water marks from staining pages you've already finished. Heavy applications of watercolor may bleed through your page to the other side, but to me this is a neat effect so I didn't try to prevent it (if you don't like bleed-through, though, apply your paint lightly and quickly.) As you progress through your pages keep those you've already painted separated with your wax paper or laminated cardboard as general dampness can also cause them to stick together.
I haven't yet finished the journal, as I wanted to completely redo the outside covers, and I'm thinking about sewing a cover out of fabric with the lock and key set you see in the next-to-last photo in the slideshow. I also want to do something with my wax paper pieces from the project, as some paint transferred to them in interesting ways (see the last picture in the slideshow.)
The great part of this project is that you don't have to bind the pages to the cover; once you're finished painting you have a finished journal. But if you want to make your own binding and covers you can remove the signatures from an existing book and rebind them once you've finished watercoloring and drying them.