Physical copy If you live in the UK please order online direct from the UK publisher, New Generation. You can also order from all major bookshops if they do not have copies in stock. 
Buy and download the eBook version for €4.99 
(select from alphabetical list)
If you live in Spain then please order online from ReadOnTime If you live elsewhere in the EU then feel free to order from ReadOnTime or even Amazon (though ideally not). I recommend non EU-based buyers use Amazon.com. There is also a Kindle version. 