> For the complete documentation index, see [llms.txt](https://programmingblockchain.gitbook.io/programmingblockchain/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://programmingblockchain.gitbook.io/programmingblockchain/introduction/crowdfunding_this_book.md).

# Crowdfunding this book

If we want to continue to make great stuff for you we need to buy pizza, sushi and coffee. It is our responsibility to get enough coins for that. Also, we are too lazy to keep writing a whole book without hearing your feedback.\
**Bitcoin address:** [1KF8kUVHK42XzgcmJF4Lxz4wcL5WDL97PB](https://blockchain.info/address/1KF8kUVHK42XzgcmJF4Lxz4wcL5WDL97PB)

As cryptocurrency addicts might say: Proof of Stake and Proof of Work are the best expression of affection, everything else is Fiat.

Find out more about our work at <http://n.bitcoin.ninja/>