The Dragon of the Month Club, by Iain Reading (CreateSpace 2014), is a fun portal fantasy with some of the nicest dragons I've read about all year.
A chance encounter in their town's library makes Ayana and Tyler friends--both are outsiders, Ayanna because she is new to town, Tyler because he's a quirky geek. And a chance encounter of Ayana's foot with a library shelf makes their new friendship into a magical partnership, when "How to Conjure Your Own Dragon in Six Easy Steps" falls at their feet. The magical conjuring promised by the book really works, and before they know it, the two kids are members of the Dragon of the Month club. Every month the book offers them the opportunity to conjure a new dragon, and happily the dragons are friendly, cooperative, and easily de-conjured again. But when they conjure a steam dragon for the first time, they slip up...and find themselves thrown outside of our world, into a land that's a world-sized recreation of Tyler's bedroom.
All the furniture is transformed to geographical features, and the land is populated by characters from the books Tyler had lying around. The two of them can't think of any way to get home on their own, so they decide to journey across the bedroom land to the tower where a wise scientist (from a factual book series) lives, in the hopes that he can help them. Some of the books that are now part of reality are not nice at all, like the German fairy tales they find themselves in first. Others are fun adventures--the Fremen of Dune are helpful, to a point, and their adventure with Sherlock Holmes is lots of fun. But it takes all of Ayana's and Tyler's dragon conjuring skills to bring them the help they need, and it was delightful to meet all the dragons (it's a really nifty assemblage of dragon-ness!).
The ending, though, is an utter cliffhanger, promising even more, ramped up and dangerous, adventure to come before they can get home again!
It's a solid book; Ayana and Tyler are perfectly fine young protagonists, and the dragons are delightful! The portal fantasy is coherently interesting, and I appreciated that the encounters with fiction (an idea that's been used a lot in middle grade fantasy recently) were ones I'd never seen in similar book-world stories. That being said, a large part of the fun comes from knowing the stories in question; Dune and Sherlock Holmes might not have been read by the target audience yet!
Short answer-- kids of eleven or so who love dragons might well enjoy it lots. A tad too episodic for my own personal taste, but that's the nature of the story.