I really miss the “Book by Its Cover” blog, especially the series of posts about sketchbooks. (The blog has been inactive since 2015 but the archives are still viewable.) Here’s a cool post I’d flagged a few years ago:

Book By Its Cover » Sketchbook Series: John Garcia.

I love this shot of John’s pile of sketchbooks:

The interiors show a lot of variety:

There are additional images in the original post. You can see John Garcia’s other work at his website.