For those who want to go beyond ‘rich results’ and learn how to use syntaxes like Microdata, RDFa, and JSON-LD; those who are struggling with metadata modeling and to understand how it relates to content, SEO, and the schema.org vocabulary.
Guides based on years of reading specifications, lots of trial-and-error, and schema.org community participation. Nevertheless, I do not know everything and make mistakes, so please reach out if you spot something amiss in my documentation.