”Where can I buy the Hanoi Rocks book in English?”

At the moment, in April 2020, the best options seem to be

Cleopatra’s Online Shop and Record Shop X = Levykauppa Äx.

More links below. Let me know if there are other options, and I’ll update.

eBay

Backstage Rock Shop

Amazon.com

Amazon co.jp

Amazon.de

Amazon.es

Amazon.fr

Amazon.it

Deadline Music

Amazon.co.uk

Giunti al Punto (Italia)