Comics really do help developing readers. I've seen it firsthand. When my daughter, Angelica, first started picking up my old Calvin and Hobbes collections she would come downstairs and tell my wife and I the funny things Calvin did. Then, slowly, she started coming downstairs and telling us the funny things Calvin said.
Comics are also great tools for language studies. The format of comics, that unique blend of words and pictures, allows the reader to follow a page-by-page narrative with a wealth of visual context clues, building vocabulary while being aided by the physical posture and gestures of the characters.
But, because comics are such a great tool for the developing reader, there can be a temptation to think of them as gateways to "real" reading. ("Real" reading being any kind of reading that doesn't involve a lot of artwork). I don't like the idea that one kind of storytelling is a "gateway" to another more legitimate kind of storytelling. Television shows are not gateways to movies. LARPing is not a gateway to community theater. Story is story, in all its many forms. It can be beautiful or it can be cheap, well or poorly executed in any format.
I also think this discounts the absolute glory of sitting in a treehouse on a summer day with a stack of comics, immersed in both art and story.
And kids of today who want to sit in a treehouse with a stack of comics? They are very, very lucky. They are lucky because we are living in a sort of golden age of treehouse comics. In the first Golden age of comics the world gave us Superman and Batman, Shazam, The Phantom, The Spirit and a host of great superheroes to be found on spinner racks across the country. There were romance comics and Westerns, but superheroes dominated comics.
In this new golden age kids have access to longer stories in multiple genre featuring a diverse cast of heroes. The drugstore spinner racks are mostly gone, and these comic books are shelved in libraries and bookstores.
So here is a short list of some great comics for summer reading, mostly off the top of my head and in no particular order. I'm focusing here on original, creator-owned, print works and not adaptations, company-owned characters (like Spiderman), or the wide world of webcomics. Cautious parents might want to pre-read some of these, though they are all books I'd hand to my own kids.
Around the World by Matt Phelan: three true stories of adventurers who circled the globe.
Owly by Andy Runton: wordless stories of friendship starring the best owl ever.
Mouse Guard by David Petersen: gorgeously illustrated stories of Medieval Mice trying to surviv in a world full of predators.
Cleopatra in Space by Mike Maihack: Does what it says on the box. The actual historical 15-year-old Cleopatra gets whisked off to space for adventures.
Amulet by Kazu Kibuishi: A sprawling detailed epic. (Also see Copper or anything else with Kazu's name on it).
Bone by Jeff Smith: Smith inspired a generation of creators with this massive work. Hand the collected single volume to any kid and watch them disappear for a week.
Superhero Girl by Faith Erin Hicks: A collection of short comics about a young superhero trying to figure out how the whole hero thing works. See also Friends with Boys.
Macanudo by Liniers: A collection of beautifully-drawn comic strips that are half Calvin and Hobbes, half Far Side. Highly reccomended.
Astronaut Academy by Dave Roman: Wacky, shiny spacey fun.
Hereville, How Mirka got her Sword by Barry Deutsch: A wisecracking Orthodox Jewish girl fights a troll.
Delilah Dirk and the Turkish Lieutenant by Tony Cliff: a magnificent swashbuckling adventure.
Smile by Raina Telgemeier: the story of a girl on the cusp of her teenage years who, after an accident, faces some difficult dental drama.
Anya's Ghost by Vera Brosgol: A high school coming-of-age story and a creepy ghost story.
Broxo! by Zack Giallongo: a Sword and Sorcery mystery/adventure pitting a young barbarian against a zombie horde.
Cardboard by Doug Tenapel: Sentient cardboard.
Boxers and Saints (and anything else) by Gene Yang: Two harrowing stories explore tow sides of the Boxer Rebellion in 1900's China. Part fantasy part historical fiction.
Jellaby by Kean Soo: Two kids and a big gentle purple monster.
Ojingogo by Matt Forsythe: wordless and gloriously weird.
Clan Apis by Jay Hosler: Steeped in science, this is also, somehow, a touching story about a hive of honey bees.
Giants Beware! by Jorge Aguirre and Rafael Rosado: Young Claudette lives a quiet medieval village. So she sets off with her friends to find a giant to slay.
Battling Boy by Paul Pope: a young demigod tries to save a city overrun by monsters.
Teen Boat by Dave Roman and John Green: the angst of being a teen, the thrill of being a boat.
What a diverse list from a variety of creators and their unique voices! And since it's Childrens Book Week (and May!), no matter what age you are I hope you are able to grab a stack of comics and head to the treehouse for an afternoon.