The OALD is a treasure trove of information for learners of English as a second language. I first got hold of an OALD in 1988 when I was about to enter the university. Now I use the new 9th Edition of the book. I cannot express sufficiently my gratitude to this dictionary. If I have learnt some English, it was partly because of this dictionary which brings a wealth of knowledge to the learner. It guides the student in all important aspects of the usage of the language in its limited function as a dictionary. I can recommend it to any learner without hesitation. I also recommend 'Guide to Patterns & Usage' of A S Hornby the pioneer of the AOLD. Good luck!