Sketches a Gogo by Guillem March
Self-published in 2014, and as far as I know, this is the first time Guillem March has put out a sketchbook featuring just his superhero work, and still the book does not seem to be available anywhere. In this case, I am guessing it must be due to it not being very well-known, but it's a great sketchbook with a lot of fun art.
The book seems to be March's love letter to the DC universe (mostly the bat-universe) at the end of his exclusive DC contract and the results are impressive. This is the guy who drew Gotham City Sirens and Catwoman, so you know that bat-related female characters are going to be represented here … a lot. And that's where personal taste comes in, of course. His style is very pin-upey, so by now you probably have your own idea about it.
In my opinion he's a bit hit and miss. His female line work is generally very delicate and sparse and leaves a lot of work to his colorist, who he has been working with for a while forming a great team. When he's drawing male characters, however, he seems to channel Joe Kubert and use a lot more lines than he does with the female figures. This sometimes makes up for illustrations that mix both inking styles, and are sometimes a bit unbalanced and distracting. At the end of the day, though, I really like his art.
If anything, this sketchbook should be known for being the only printed version of the infamous Catwoman unpublished page where she goes commando on Bruce Wayne's lawn. Here's a colored version:
In the sketchbook, you will also see the original art for that page, where Selina is wearing one less piece of clothing (SPOILER: it's not the wig).
I will leave you with some more art from the book but, if you like March's art, you could do a lot worse than getting a copy of this.