Status update on Mastering Bitcoin, 3rd edition: yesterday I sent my editor the first draft of Chapter 8 about digital signatures. In addition to small revisions from the second edition about ECDSA and sighashes, the draft now describes schnorr signatures, scriptless multisignatures, and scriptless threshold signatures. Plus there's now a description of the major differences between ECDSA and schnorr signatures. If I finish the remaining 6 chapters early, I hope to come back and add some information about signature adaptors.