10 adult coloring books to get your hands all over (photos)

The creator behind HBO's hit series "Game of Thrones," George R. R. Martin is currently overseeing a series of 45 illustrations for a new adult coloring book due out this fall. In doing so, he's jumping on a hot trend in publishing that is seeing coloring books for adults steadily rise in popularity. The activity is proving to be an effective stress-buster for lots of frazzled adults.

According to Publishers Weekly, this coloring book by the "queen of coloring," Johanna Basford, sold 1.5 million copies since 2013 and is largely credited with kicking off the trend of adults rediscovering their childhoods with markers, crayons and colored pencils.

"This interactive activity book takes you on a ramble through a secret garden created in beautifully detailed pen-and-ink illustrations -- all waiting to be brought to life through coloring, but each also sheltering all kinds of tiny creatures just waiting to be found," says the book's description on Amazon. "And there are also bits of the garden that still need to be completed by you."

This is the second book from Basford and it also contains a series of creatures you're meant to find as you color through the pages, which are arranged like a journey through a forest with a castle in the middle. Hidden in the pages are nine symbols on stone tablets that help unlock a puzzle at the end.

With a name that says it all, "Color Therapy: An Anti-Stress Coloring Book" is currently a number one new release in Amazon's "paper craft" category. It's uniqueness comes from the fact that the entire book is arranged according to the color palettes you're supposed to use, so you can choose a cool blue scene or one that's raging red according to your mood.

From Michael O'Mara Books, this collection features over 100 covers from vintage comics from the 1950s, "from superheroes to aliens and romantic heroes to monsters." If you've ever wanted to try your hand as a comic illustrator -- here's your chance.

The publisher also has a great feature on their website that lets you try coloring some patterns in with a click of your mouse. It's a lot easier than filling in all those pesky little lines, and it can be equally relaxing.

On the other hand, if you've ever fancied yourself a tattoo artist, here's the coloring book for you. "From tribal patterns to dragons," says the book's description, "from skulls to floral designs, this coloring book celebrates the diversity of this art form, with something here for all tastes, proving that coloring-in is not just for kids!"

Another book with a title that says it all, "The Art of Nature Coloring Book: 60 Illustrations Inspired by Vintage Botanical and Scientific Prints," is a refreshing addition to the category thanks to its unique source material.

As a testament to the fact that naming your product after something that's trending can work, this book, entitled simply, "Adult Coloring Book: Stress Relieving Patterns" is currently number 16 on Amazon's bestseller list. Its "instructions" do a great job of showing just why this activity might work tame your own personal stress monster.

For example, step number seven says: "If you notice at any point that you are having fun, forgetting your worries, daydreaming freely, feeling more creative, excitable, curious, delighted, relaxed or any combination thereof, breathe deeply and take a moment to enjoy it. Then, gently return your attention to coloring."

While the adult coloring books featured so far are meant to rid your mind of worry by having you focus on filling in small patterns, this one will bust your stress with big laughs. Created by YouTube sensations Ryan Hunter and Taige Jensen, the book is full of irony -- if not artistic beauty. One example? There's a page with a blank mirror that says: "Draw the person you thought you'd grow up to be before you abandoned all your hopes and dreams."

Definitely not one for the kiddies.

Also in the comic category, this oddball coloring book is based on the premise that unicorns can be a little less than magical sometimes.

"Unicorns think they're so great because they're all mysterious and magical, but they can be real jerks sometimes," says the description. "This coloring book features eighteen examples of unicorns texting in theaters, farting in elevators, eating your leftovers, and generally acting like jerks."

As every little kid knows, sometimes it's just more fun to color outside the lines.

In the case of this coloring book though, the phrase refers to the fact that the illustrations it contains are from a range of artists whose creativity certainly comes from thinking outside the lines. The book contains over 100 styling scenes to color in from "animators, cartoonists, fine artists, graphic artists, illustrators, musicians, outsider artists, photographers, street artists, and video game artists."