As the Wanteds, Unwanteds, and Necessaries struggle to adjust to changes in their society, Mr. Today begins training fourteen-year-old Alex to replace him as Artime's leader one day while Alex's disgraced twin, Aaron, connives to take over Quill.

Second-graders Arlene and Ilene Kelly are twins, identical twins to be exact, and they love being a pair. They love to dress alike, they have identical pet ferrets, and they do everything together. But being a twin is not always easy. And when Arlene gets sick and has to visit the hospital, the twins each find out what it's like to be one instead of two. But whether they're together or apart, Arlene and Ilene know they're lucky to have each other....

A little girl describes all the things she and her twin sister have in common.

Anthony Farrant has boasted, lied and cheated his way through jobs all over the world. Then his twin sister, Kate, gets him taken on as the bodyguard of Krogh, her lover and boss, a megalomaniac Swedish financier. All goes well until Krogh gives orders that offend Anthony's innate decency.

Ivy Gamble was born without magic and never wanted it. Ivy Gamble is perfectly happy with her life - or at least, she's perfectly fine. She doesn't in any way wish she was like Tabitha, her estranged, gifted twin sister. Ivy Gamble is a liar. When a gruesome murder is discovered at The Osthorne Academy of Young Mages, where her estranged twin sister teaches Theoretical Magic, reluctant detective Ivy Gamble is pulled into the world of untold power...

Another case of mistaken identity from the king of the plot twist, Twelfth Night tells the tale of the beautiful young Viola who is separated from her twin brother, Sebastian, when their ship is lost at sea. Believing Sebastian to be dead Viol poses as a man and enters service with the Duke Orisino. When Olivia, the woman that Orisino loves, falls for his messenger "boy" Viola and she in turn falls for the Duke the stage is set for a classic

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"Tween twins Coke and Pepsi McDonald have finally reached the last leg of their wacky and dangerous cross-country road trip, but they must fend off a host of strange assassins before they reach their home in California"-- Provided by publisher.

After she betrays her identical twin, Jessica Wakefield longs for forgiveness, but Elizabeth moves from Sweet Valley, California, to New York City and searches for the perfect revenge.

"Beware Four-winged Blackbird," is the warning that introduces the Bobbsey twins to mystery in Canada where they search for a missing friend.