The release of the extraordinary new book by Brian Selznick got us thinking about books that defy easy categorization and are suitable for readers who like to question everything, consider the big philosophical questions of life, and formulate their own conclusions - or even realise that there are no simple answers to many of our most challenging questions.

As well as the stunning Selznick, here are some other wonderfully inspiring recommendations for deep thinkers of all ages.

Kaledeidoscope by Brian Selznick

The incomparable Brian Selznick presents the story of two people bound to each other through time and space, memory and dreams. At the centre of their relationship is a mystery about the nature of grief and love, which will look different to each reader.

Kaleidoscope is a feat of storytelling that illuminates how even the wildest tales can help us in the hardest times. With incredible illustrations at the start of each chapter, it can be read as a collection of loosely interlinked short stories or a journey on an understanding of loss and love.

Suitable for readers aged 10 to adult.

Big Ideas for Curious Minds by the School of Life

Children are, in many ways, born philosophers. Without prompting, they ask some of the largest questions: about time, mortality, happiness and the meaning of it all. Yet sadly, too often, this inborn curiosity is not developed and with age the questions fall away. This is a book designed to harness childrens’ spontaneous philosophical instinct and to develop it through introductions to some of the most vibrant and essential philosophical ideas of history.

The book functions as an ideal introduction to philosophy as well as a charming way to open up conversations between adults and children about the biggest questions we all face.

Suitable for readers aged 7 and up.

Poison for Breakfast by Lemony Snicket

One day, Lemony Snicket finds a puzzling note pushed under his door and is forced to follow a winding trail of clues to solve the mystery of his imminent death.

Along the way, he tackles some of the key questions about life. What are the three absolute rules for writing a book? Why should you never judge a goat by the way it looks? And why does being clumsy have its benefits? Also, what came first - the chicken or the egg?

Lemony Snicket has led millions of young readers through a world of bewildering questions and strange, unfortunate events. This latest book takes us on a thought-provoking tour of his own predilections.

Suitable for readers aged 10 and up.

Big Ideas for Young Thinkers by Jamia Wilson

Stylish and accessible, this book teaches children to think critically in a world which needs young thinkers.

Jamia Wilson expertly explores the difficult questions. Each question is introduced in lively prose before a timeline lays out how different thinkers of the world have approached them.

Questions include: Who are you? Why do we exist? What happens when we die? What is right and wrong? What is an imagination?

This book brings philosophy to the next generation.

Suitable for readers aged 7 and up.

Sophie’s World by Jostein Gaarder

The international bestseller about life, the universe and everything.

When 14-year-old Sophie encounters a mysterious mentor who introduces her to philosophy, mysteries deepen in her own life. Why does she keep getting postcards addressed to another girl? Who is the other girl? And who, for that matter, is Sophie herself? To solve the riddle, she uses her new knowledge of philosophy, but the truth is far stranger than she could have imagined.

We are the white rabbit being pulled out of the hat. The only difference between us and the white rabbit is that the rabbit does not realize it is taking part in a magic trick.

Suitable for readers aged 11 to adult.

There Must be More Than That! by Shinsuke Yoshitake

Readers of all ages will seek solace in this smart and spirited exploration of the good that might be right around the corner.

There Must Be More Than That! takes an unflinching look into an uncertain ever after and spins out scenarios that are at once reassuring, ridiculous, and a reminder that we all have the power to choose our own mindsets.

After all, a promising outlook is in our heads as much as it is in our hands-it’s often just a matter of choosing hope over hopelessness, and seeking an affirming alternative to challenging situations.

Suitable for ages 4 and up.