I’ve been listening to a lot of audiobooks and podcasts while working on illustrations lately. A great resource for this is LibriVox which features readings of works which are in the public domain. A great one I recently toiled to was The Invisible Man by H.G. Wells which was written in 1897 and is an absolute sci-fi classic.
The image above of The Invisible Man (who is also a co-founder of this website) was done in my sketchbook a while back and tweaked digitally.