When Nephele has a terrible freshman year, she does the only logical thing for a math prodigy like herself: she invents a time travel app so she can go back and do it again (and again, and again) in this funny love story , Groundhog Day for the iPhone generation. Fourteen-year-old Nephele used to have friends. Well, she had a friend. That friend made the adjustment to high school easily, leaving Nephele behind in the process. And as Nephele looks ahead, all she can see is three very lonely years. Nephele is also a whip-smart lover of math and science, so she makes a plan. Step one: invent time travel. Step two: go back in time, have a do-over of 9th grade, crack the code on making friends and become beloved and popular. Does it work? Sort of. Nephele does travel through time, but not the way she planned--she's created a time loop, and she's the only one looping. And she keeps looping, for ten years, always alone. Now, facing ninth grade for the tenth time, Nephele knows what to expect. Or so she thinks. She didn't anticipate that her new teacher would be a boy from her long ago ninth grade class, now a grown man; that she would finally make a new friend, after ten years. And, she couldn't have pictured someone like Jazz, with his deep violet eyes, goofy magic tricks and the quietly intense way he sees her. After ten freshman years, she still has a lot more to learn. But now that she's finally figured out how to go back, has she found something worth staying for? Nephele Weather wants to fix her freshman year. Abandoned by her best friend, Vera Knight, for the cool crowd and bullied by her classmates--for the hairiness imparted by her Greek heritage and being exceptionally good at math--Nephele decides not to move forward but to go back...in time. Eschewing a Whovian T.A.R.D.I.S. or Wellsian machine, prodigy Nephele creates Dirk Angus, her quantum-foam-manipulating phone app, only to discover that she's reset but others are not; with each reiteration, Nephele redoes ninth grade but can't win back Vera, as everyone ages except her. Tying herself and the universe in knots, Nephele learns about love and loss, discovering that she can't change the past, but she could be warping the future. Lariviere revels in math and science, unabashedly celebrates science fiction and romance novels, and anchors the story in a realistic, comfortably cozy coastal Californian setting. The lack of catastrophic, explosion-riddled scenes, evil overlords, or alien invasions renders this a gentle, grounded read, reminiscent of A Wrinkle in Time. Most students read as White; math and science teacher Mrs. Saint Johnabelle, a mentor figure, reads as Black. A heartwarming story of hacking high school through math. (Science fiction. 12-18)-- Kirkus Reviews 10 Outstanding Fall Titles for Teens-- Kirkus Reviews After her friend Vera ghosts her, "aggressively weird" Nephele Weather, 14, begins to obsess over why--whether it's her math obsession or her hirsute Greek heritage--and how to fix it. That's how mathematics ("my one superpower") comes into play. Armed with her knowledge of all things numerical, a strange book found at her parents' bookstore, and her science teacher's assistance, she devises a time travel app named Dirk Angus to change the past. Things, of course, go awry: while Nephele remains the same age, others mature a year every time she goes back, and by her 10th journey, she is no closer to her goal--in fact, that goal has morphed into something new but no less terrifying. Lariviere's ( The Bad Kid ) YA debut is a multifaceted mélange of math and hormones; Nephele's introspective monologues are filled with elegantly descriptive detail, tending toward a rambling stream-of-consciousness that many readers will find winning. Ages 12-up. -- Publishers Weekly Time Loops and Multiverses: A Children's and YA Book List-- Publishers Weekly For "Fans of Scott Westerfeld's YA sci-fi and the whimsy of Dr. Who"-- School Library Journal "Captivating and wildly creative, Time Travel for Love and Profit gave me that thrill of excitement you feel when you find a new YA voice that you know will become one of your favorites."-- Rachael Allen, author of A Taxonomy of Love and The Summer of Impossibilities "This bittersweet, beautifully funny novel is wonderfully weird and infinitely loveable. Staying up all night reading it is like an all-time memorable sleepover with your best, most oddball friend."-- Harriet Reuter Hapgood, author of How to Be Luminous "A wild and funny ride through that most treacherous time of all: freshman year. This is a wise and timely reminder that there are no do-overs in life!"-- Brent Hartinger, author of Geography Club and The Otto Digmore Difference "Smart, tender and deliciously nerdy."-- Ariel Kaplan, author of We Are the Perfect Girl Sarah Lariviere's debut middle grade novel The Bad Kid (Simon & Schuster Books for Young Readers) was a 2017 Edgar Award finalist. Sarah grew up