Author here. No publishing date has been set yet. At least a half-written Japanese version of the book is available online for free (https://www.sigbus.info/com

Author here. No publishing date has been set yet. At least a half-written Japanese version of the book is available online for free (https://www.sigbus.info/compilerbook https://www.sigbus.info/compilerbook), and I'll probably translate this to English and share at least a few chapters for free. But nothing is set in stone yet. There's no mailing list for notifications yet.