can't buy bitcoin eBook using bitcoin? It sounds like a headline from The Onion, but is it really true?  I can't find anywhere I can buy the eBook Mastering Bitcoin using bitcoin, only PayPal or Credit Card.
He suspended sales because the original print run ran out. The merchants that accept paypal/credit cards are only accepting preorders.

He posts availability info on his website:

https://www.bitcoinbook.info/

In the meantime, he's published the book online.