When I taught myself English a long time ago I used (alongside Assimil's L'anglais sans peine and the BBC's Calling all beginners) a series of four books, Essential English authored by C.E. Eckersley and published by Longmans.
It was an impressively good set of boooks, with plenty of grammatical and cultural explanations, presented in a very British witty and amusing style and accompanied by funny but quite relevant cartoons and schematic drawings.
My question is whether English is still taught from these textbooks.
I confess that I was emboldened to ask this question by the mischievous thought that for once you native English speakers would be at a disadvantage to answer it (unless you teach English) as compared to us foreigners ...