Which formats are Librio books available in?

Our books come in two formats: Hardback and Paperback. 

Although the cheaper of the two options, the paperback is a super high quality product and is designed to withstand the rigours of being owned by a young child. 

The hardback is a notch more durable than the paperback. 

Funny how they're not called Hardfront and Paperfront. Would seem to make more sense. Then again, Paperfront Writer would have been a rubbish name for a Beatles song.