Poseidon: Earth Shaker (First Second, March, 2013) is the fifth of the Greek gods to get his own graphic novel, in the stellar series written and illustrated by George O'Connor.
The series as a whole is an extraordinarily kid-friendly introduction to the Greek pantheon, and although I wouldn't recommend starting with Poseidon, this latest volume is a fine addition to the series.
It's somewhat episodic, beginning with the division of the cosmos between the three main gods (Zeus, Hades, and Poseidon), with Poseidon revelling in his new dominion over the sea. The stories of Odysseus and how he outwitted the Cyclopedian (Cyclopsian?) son of Poseidon, and Theseus, another son, come next, followed by the story of the contest between Poseidon and Athena over Athens. The story concludes with a flashback back to the early struggles between the gods and the Titans, emphasizing the overall theme of the book--Poseidon's conflict between the joy he takes in his dominion of the sea, and his sense that somehow he has been wronged.
Though this is a kid-friendly series, it's not something I'd give to a kid younger than ten or so--there are "adult themes" as is so often the case when one deals with the Greek gods...But for the older, perhaps reluctant reader, this series is a spot-on introduction to the stories--the pictures are powerful and utterly memorable (true for all the books, but I think in this book they are particularly compelling, what with all the ocean action opportunities provided by the subject matter), swinging the events along very nicely indeed. Adding value for teachers, and written in a manner engaging enough for the curious young reader, there's interesting back-matter included as well.
(review copy received from the publisher)