Fine series for the serious student
Part of a series in various languages, I find this book indispensable for delving into the Spanish language. It reflects the language in three different registers: R3 is elevated usage; R2 is normal colloquial use without dipping into slang or jargon; R1 is the youth, underworld argot, etc., as well as very familiar usage.
One can avoid many pitfalls armed with a bit of knowledge.
