This is something I have been wanting to try. I used Sculpey polymer clay to make the covers.
The clay wouldn't get as hard as it should have. It's still pliable.
The pages are mat board. This is a rough experiment at best I love things with textures and this certainly has that.
I had a couple swatches of curtain fabric, so I added them, too.
This one was quicker and easier than I expected.
I used construction paper and colored pencils.
Now I have that song "i can sing a rainbow" going through my head...