“Mastering Photoshop is written for advanced and intermediate designers who want to brush up on their workflow and improve their Photoshop skills. The eBook contains 178 pages, explaining fundamental techniques that Web designers need to know to produce high-quality work in Photoshop. You won’t find any generic step-by-step tutorials or learn random effects. You will gain a profound understanding of what you can do with Photoshop and how to use it effectively in your work.”
I used quite a few Smashing Magazine tutorials over the years, they are simple to follow but go further than most in explaining the details. This is a PDF eBook so it should be a great read on the iPad and if you really need to have it printed, 178 pages won’t break the bank.