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Kay’s Brilliant Brains

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Written by: Adam Kay
Illustrated by: Henry Paker
Publisher: Puffin (Penguin Random House Children's)

One hundred billion people have lived on earth. Unfortunately, this book would be too heavy if it talked about them all, so it’s only about ten of them.

They were all just ordinary people like you and me who were sitting around scratching their bums and wondering what time dinner was going to be ready, when one day they thought ‘Oh, I’ve got an idea’ and suddenly changed the world forever.

You might have heard of some of them.

Like Ada Lovelace, who invented computer programming two hundred years ago. (But was banned from going into libraries.)
Or Thomas Edison, who invented movie cameras and lightbulbs and how to record music. (But only went to school until he was twelve.)
And Amelia Earhart, the first woman to fly across a huge ocean, back in the days when planes were made of bits of old wood and looked like they might fall apart any second. (And worst of all, they didn’t have in-flight movies.)

Containing 4,523,825 facts (this is a guess), KAY’S BRILLIANT BRAINS is written and illustrated especially for World Book Day 2023 by the record-breaking Adam Kay and Henry Paker. It’s a hilarious celebration of ten of the world’s most ingenious geniuses and all that their brilliant brains achieved.

PS Dinner’s at 6:30.

Find your local bookseller View video on Vimeo Download activity sheet


The £1/€1.50 books are also available in braille, large print & audio via Guide Dogs, NCBI, RNIB and Calibre Audio. If you require one of these formats, please get in touch with the following contact numbers closer to World Book Day:

RNIB – Braille & audio versions (UK) 0303 123 9999
Guide Dogs – Large print (UK) 0345 143 1000
Calibre Audio – Audio versions (UK) 01296 432 339
NCBI – Braille, audio, large print (Ireland) 01 8642266 (or email

    About the Author

    Adam Kay

    Adam Kay is an award-winning writer and former non-award-winning junior doctor. His first book, This is Going to Hurt: Secret Diaries of a Junior Doctor, was a Sunday Times number-one bestseller for over a year and has sold over 2.5 million copies. His new memoir Undoctored: The Story of a Medic Who Ran Out of Patients is published in September 2022. His first children’s book, Kay’s Anatomy, was published in October 2020 and became the fastest-selling children’s general non fiction hardback of the decade and rights across Kay’s Anatomy and Kay’s Marvellous Medicine have now been sold in 28 languages.


    Adam Kay

    About the Illustrator

    Henry Paker

    Henry Paker

    Henry Paker is an award winning comedian, writer and illustrator. His cartoons have been published in The Times, Observer and Spectator. He co-writes and performs in the Radio 4 sitcom ReincarNathan and co-hosts the Three Bean Salad podcast. Henry has illustrated all of Adam’s children’s books.


    Other great £1/€1.50 books for you to enjoy

    • A Dragon Realm Adventure
    • Katie & Kevin Tsang
    • Simon & Schuster Children's Books
    • The Strangeworlds Travel Agency: Adventure in the Floating Mountains
    • L.D. Lapinski
    • Hachette Children's Group
    • Hazel Tree Farm: One Stormy Night
    • Alma Jordan
    • Margaret Anne Suggs
    • The O'Brien Press
    • The Boy with Wings: Attack of the Rampaging Robot
    • Lenny Henry
    • Keenon Ferrell
    • Macmillan Children's Books
    World Book Day® is a charity sponsored by National Book Tokens.