From samplers and author panels to signings and galleys of science fiction and fantasy novels, major book publishers such as Penguin Random House and HarperCollins are once again investing heavily in promotional materials for the five days of Comic-Con International, held at the San Diego Convention Center. The annual pop-culture convention draws more than 130,000 attendees and offers programming related to comics, film, books and related media. Book publishers see it as an incredible promotional platform.

Comic-con may celebrate comics but the fans are on the lookout for books and related media of all kinds. Over the weekend, HarperCollins and its partners are set to preview an interactive, multimedia project based on writer James Frey's Endgame trilogy, which chronicles teens hunting for ancient keys that could save the world. At its core, the project is an augmented reality game that allows players, using their smartphones, to scavenge for items around Comic-Con. Endgame is also getting the film treatment by 20th Century Fox. Frey, HarperCollins, Google's Niantic Labs and 20th Century Fox collaborated on the project, and they're planning panels, signings, access codes to games.

Comic-Con is a fitting place to launch the project because of its media convergence, says Sandee Roston, executive director of publicity of HarperCollins Children's Books, the division that publishes the Endgame series.

"The innovative mobile game adds interactive real-world experiences to Endgame, merging story with social activation to create a fully immersive world," Roston told PW on Friday.

Across from the HarperCollins booth, the Penguin Group of publisher Penguin Random House kicked off their Comic-Con promotions earlier this week with giveaways of advanced reader copies of science fiction, steampunk and dystopian novels. ‎Assistant manager of marketing and advertising Mia Garcia said Penguin brought more than 3,000 books for the taking.

"They always know they can come to the Penguin booth and get a new book," she said, a line of people wrapping around the booth.

Comic-Con was also the launch of Penguin's Comic-Con-themed Mad Libs book, which allows readers to plug in nouns, verbs and more for humorous results. In response to last year's popularity, Penguin is giving away 5,000 copies at a Mad Libs pop-up booth instead of Penguin's. "It's really hard to get space at Comic-Con," Garcia said, "so our licensing team really wanted to represent some of our big licensors, like Adventure Time," a series on Cartoon Network.

While publishers are trying to maximize the exhibit space they have at Comic-Con, they're also focused creative ways to get the attention of badgeholders walking around the Comic-Con's exhibit hall, which holds hundreds of vendors. From Macmillan imprints like Tor and First Second Books, to Hachette Book Group and and Random House, there are many cases of author panels followed before and after by signings. Those are promoted online and when Comic-Con attendees come to booths for various promotional items.

To promote their latest offerings, Simon and Schuster came to Comic-Con with chapter samplers, buttons, temporary tattoos and more, with hundreds in quantity. The publisher also brought journals related to Scott Westerfeld's new book, Afterworlds, about a young writer with rapid success in light of writing a novel.

Chrissy Noh, associate director of marketing of Simon and Schuster Children's Publishing, said the fans are quick to grab anything related to the books and authors they love. "I could literally put everything out tonight, and it would all be gone by tomorrow,” she said.