Top 20 Best Books of the Year 2015 as Selected by Actual Readers
Here are the best books of 2015 as selected by real readers. The list was released by book recommendation website Goodreads from their annual 2015 Goodreads Choice Awards. Over 3 million votes were cast.
There were winners from 20 categories. Here's the list with a short description from Goodreads.
BEST FICTION
Go Set a Watchman by Harper Lee
From Harper Lee comes a landmark new novel set two decades after her beloved Pulitzer Prize-winning masterpiece, To Kill a Mockingbird.
BEST MYSTERY & THRILLER
The Girl on the Train by Paula Hawkins
A debut psychological thriller that will forever change the way you look at other people’s lives.
BEST HISTORICAL FICTION
The Nightingale by Kristin Hannah
With courage, grace and powerful insight, bestselling author Kristin Hannah takes her talented pen to the epic panorama of WWII and illuminates an intimate part of history seldom seen: the women’s war.
BEST FANTASY

In this new anthology, Neil Gaiman pierces the veil of reality to reveal the enigmatic, shadowy world that lies beneath. Trigger Warning includes previously published pieces of short fiction--stories, verse, and a very special Doctor Who story that was written for the fiftieth anniversary of the beloved series in 2013--as well "Black Dog," a new tale that revisits the world of American Gods, exclusive to this collection.
BEST ROMANCE

From #1 New York Times bestselling author Colleen Hoover, a new novel about risking everything for love—and finding your heart somewhere between the truth and lies.
BEST SCIENCE FICTION

With shades of The Hunger Games, Ender’s Game, and Game of Thrones, debut author Pierce Brown’s genre-defying epic Red Rising hit the ground running and wasted no time becoming a sensation. Golden Son continues the stunning saga of Darrow, a rebel forged by tragedy, battling to lead his oppressed people to freedom from the overlords of a brutal elitist future built on lies. Now fully embedded among the Gold ruling class, Darrow continues his work to bring down Society from within. A life-or-death tale of vengeance with an unforgettable hero at its heart, Golden Son guarantees Pierce Brown’s continuing status as one of fiction’s most exciting new voices.
BEST HORROR

The hugely anticipated finale to #1 New York Times bestselling author Dean Koontz's acclaimed Odd Thomas series, featuring his most popular character-a thrilling tour-de-force packed with suspense and emotion that gives fans everything they've been waiting for... and much, much more.
BEST HUMOR

In Why Not Me?, Kaling shares her ongoing journey to find contentment and excitement in her adult life, whether it’s falling in love at work, seeking new friendships in lonely places, attempting to be the first person in history to lose weight without any behavior modification whatsoever, or most important, believing that you have a place in Hollywood when you’re constantly reminded that no one looks like you.
BEST NONFICTION

A hilarious, thoughtful, and in-depth exploration of the pleasures and perils of modern romance from one of this generation’s sharpest comedic voices
BEST MEMOIR & AUTOBIOGRAPHY

In this intimate memoir of life beyond the camera, Connor Franta shares the lessons he has learned on his journey from small-town boy to Internet sensation so far.
BEST HISTORY & BIOGRAPHY

From the bestselling author and master of narrative nonfiction comes the enthralling story of the sinking of the Lusitania
BEST SCIENCE & TECHNOLOGY

In Beneath the Surface, Hargrove paints a compelling portrait of these highly intelligent and social creatures, including his favorite whales Takara and her mother Kasatka, two of the most dominant orcas in SeaWorld. And he includes vibrant descriptions of the lives of orcas in the wild, contrasting their freedom in the ocean with their lives in SeaWorld.
BEST FOOD & COOKBOOKS

The Pioneer Woman Cooks: Dinnertime is a beloved collection of all the scrumptious supper recipes that make their way through my kitchen in regular rotation, from main dish salads to satisfying soups to hearty casseroles to comfort food classics . . . and everything in between. I lay out all the different ways I tackle dinner in my house, from super-quick 16-Minute Meals to make-ahead Freezer Food to irresistible pastas and a bundle of brand-new favorites of my crew.
BEST GRAPHIC NOVELS & COMICS

From the Eisner Award-winning duo of Brian K. Vaughan (The Private Eye, Pride of Baghdad) and Fiona Staples (Mystery Society, Thor, SAGA is the sweeping tale of one young family fighting to find their place in the universe. As they visit a strange new world and encounter even more adversaries, baby Hazel finally becomes a toddler, while her star-crossed parents Marko and Alana struggle to stay on their feet.
BEST POETRY
The Dogs I Have Kissed by Trista Mateer
Known for her eponymous blog and her confessional style of writing, this is Trista Mateer's second collection of poetry.
BEST DEBUT GOODREADS AUTHOR

Graceling meets The Selection in debut novelist Victoria Aveyard's sweeping tale of seventeen-year-old Mare, a common girl whose once-latent magical power draws her into the dangerous intrigue of the king's palace. Will her power save her or condemn her?
BEST YOUNG ADULT FICTION

The Fault in Our Stars meets Eleanor and Park in this exhilarating and heart-wrenching love story about a girl who learns to live from a boy who intends to die.
Soon to be a major motion picture starring Elle Fanning!
BEST YOUNG ADULT FANTASY & SCIENCE FICTION

The fourth volume in the New York Times bestselling series continues Celaena’s epic journey and builds to a passionate, agonizing crescendo that might just shatter her world.
BEST MIDDLE GRADE & CHILDREN'S
Magnus Chase and the Gods of Asgard, Book 1: The Sword of Summer by Rick Riordan
Magnus Chase has always been a troubled kid. Since his mother's mysterious death, he's lived alone on the streets of Boston, surviving by his wits, keeping one step ahead of the police and the truant officers.
BEST PICTURE BOOK

The companion to the #1 blockbuster bestseller, The Day the Crayons Quit!
A Wall Street Journal Best Children's Book of 2015 / A TIME Magazine Top 10 Children's Book of 2015