Dictionaries exist in order to answer questions. To help us to give the right answers to the right questions, we – as dictionary makers – need to know who will be using the dictionary and what kinds of information they really need. All of this means making a careful selection from the enormous amount of data available to us. So how do we decide what is really 'essential', and how can we be sure that we have made the right selection?

In creating the Macmillan Essential Dictionary, we have benefited from two valuable resources:

• high-quality linguistic data: our large language corpora and advanced software give us the tools to identify the essential facts about English
  
  
• expert advice: at every stage, experienced teachers, coursebook writers, and language students have contributed their suggestions and comments, telling us what learners really need to know