The giant sail-backed carnivorous dinosaur Spinosaurus is one of the most famous dinosaurs in the world – a staple of documentaries, books and games, and one that bested the mighty T. rex in Jurassic Park II. But what do we actually know about this crocodile-headed monster and its relatives, the spinosaurs?

Despite our growing fascination with them, there is a great deal of mystery surrounding these animals – how they lived, what they fed on, even what they looked like. What we can say for sure is that the spinosaurs include some of the strangest-looking of all dinosaurs, combining a long and low skull with a crest along the spine that extends into a huge sail, a fin-like tail, and strong, massively clawed hands. Their appearance was unlike anything else – they were truly bizarre animals.

Interpreting their lifestyle remains a stern challenge for palaeontologists, and the spinosaurs are a controversial group indeed. Their remains have been found worldwide, but they are highly fragmentary; many aspects of their appearance are uncertain, their evolutionary relationships are elusive, and there are profoundly different competing interpretations of their ecology and behaviour circulating in the scientific literature. As a result, spinosaurs have had more focus than any other dinosaur group in recent years, and new discoveries and papers continue to draw huge media attention.

There remains much that is unknown about the spinosaurs, but what we do know points them out as one of the most interesting, unusual and charismatic of all prehistoric animal groups. This book, by world-renowned palaeontologists David Hone and Mark Witton and enlivened by the latter's illustrations, summarises what's known about them and what isn't, and looks in detail at the latest theories on how these mighty beasts lived, fed, bred and died.