After squashing Darwin deniers and God-botherers with bestselling tomes including The God Delusion and The Greatest Show on Earth, Richard Dawkins is set to tackle what might be his hardest audience yet: teenagers.

The well-known scientist and atheist has struck a book deal for his first title for young adults, which will look to explode myths and legends about the natural world with science. Due out in autumn 2011, What is a Rainbow, Really? will take on topics including who the first man and first woman were, why there are seasons, what the sun is, how old the world is and why there are so many animals, first answering the questions with myth and legend, and then with "lucid scientific explanations".

"Richard has always been incredibly keen to reach children from the whole point of view of individual critical thinking and not to just toe the party line," said Sally Gaminara, who bought the book for Transworld, part of the Random House Group. "He will explore certain myths people are brought up with – he's very keen to do that, to make people look at things and not be accepting, to question more ... He will tell myths for what they are but will also delight in their poetic beauty."

The book will be illustrated by Dave McKean, who has previously worked on books by David Almond and Neil Gaiman. "It's for young adults of 12 and upwards but it will also appeal to the curious child and to adults as well," said Gaminara. "It will be a really rich and rewarding and inspirational sort of book."

Dawkins's previous books, including The Selfish Gene and The Blind Watchmaker, have sold more than 1.2m copies to date, according to book sales monitor Nielsen BookScan. His diatribe against religion, The God Delusion – which describes the God of the Old Testament as "a misogynistic, homophobic, racist, infanticidal, genocidal, filicidal, pestilential, megalomaniacal, sadomasochistic, capriciously malevolent bully" – is by far the most popular, with more than 700,000 copies sold since it was first published in 2006. His latest, The Greatest Show on Earth (which lays out the evidence for evolution) has already sold almost 45,000 copies little more than a month after it was published.