The grammar items are cleverly rated so you can determine what's most useful for you to study, based on your Korean knowledge level and your plans. There is a star rating system, from 5 stars ("critical"; with these under your belt you can communicate almost everything you need to say) to 1 star (don't worry about this unless there's some reason you need to know it—for example, the TOPIK exam). Essential Korean Grammar is a toolbox to help you form correct and natural-sounding sentences, and determine which grammar you need for reading or writing Korean. It details:How to combine grammar points with each type of word.How it is similar to and different from related grammar points.Commonly used expressions.Things for learners to watch out for.