"When her former best friend gets popular and leaves her behind, sixth-grader Ruth prefers to be alone, studying for the school spelling bee, until she finds a riddle in an old book." --

Pepper and Jake, sister and brother shepherds, match wits with the giant, Urk, who regularly floods their valley with his dirty washwater.

When students in Mr. Tiffin's class are invited to solve a riddle during a field trip to an apple orchard, it is Tara's daydreams that may lead to the answer.

Their magic tree house takes Jack and Annie deep into the sea, where they meet up with dolphins, sharks, and octopi as they search for the answer to an ancient riddle.

Ten-year-old Flavia and her friends encounter the Roman admiral Pliny before making a journey to her uncle's farm near Mt. Vesuvius, where they try to solve a riddle, reunite a family, and get out of the path of a natural disaster.

Anouk, Ben and Cara dream of a fabulous treasure buried on the golden island across the harbor. A mysterious and grizzled old man offers them passage on his boat, but only if they can solve seven vexing riddles. If they succeed, a strange and magical prize awaits them. -- Amazon.com

"The Robber Girl has a good dagger. Its voice in her head is as sharp as its two edges that taper down to a point. Today, the Robber Girl and her dagger will ride with Gentleman Jack into the Indigo Heart to claim the gold that's rightfully his. But instead of gold, the Robber Girl finds a dollhouse cottage with doorknobs the size of apple seeds. She finds two dolls who give her three tasks, even though she knows that three is too many tasks. The...

"When Celia and Tyrus discover the four lost diaries of Charles Dodgson (a.k.a. Lewis Carroll), they are pulled into Wonderland and must solve riddles and puzzles to stop the Queen of Hearts from opening a door and taking over our world"--

After moving with her parents to a remote English island, fourteen-year-old Jess attempts to dispel an ancient curse by solving a series of riddles, aided by Epsilon, a supernatural being.

"Batman has been kidnapped by the Riddler! The crook has left behind one of his infamous riddles, addressed to Robin. If Robin can solve the puzzle, he will locate the Caped Crusader, but that first riddle leads to another. Then the Riddler turns off all the lights in Gotham City. What, Robin wonders, is the point? When will the riddles end? If the Boy Wonder cannot find his partner by the next sunrise, Batman will be gone forever"--P. [4] of cover....