Raymond Murphy interview - Grammar in Use over the past 30 years

Celebrating 30 years of Grammar in Use. 

Author Raymond Murphy discusses how Grammar in Use, the world's best-selling grammar series for learners of English, has evolved since its first publication by Cambridge University Press in 1985.

Many of us have learned and taught with this series... Congratulations on the anniversary!!!
Find useful phrases to refer to language learning: "self-study book", "essential reference tool", "not being wordy", "appropriate to the task", "study guide", "diagnostic tests" ... form an expert!.
Very easy to read and understand phrases but somehow difficult to produce on our own and put in our mouths!