Is your English good, but still not fluent and natural?

Advanced Everyday English is book 2 in the Everyday English series (book 1 is Practical Everyday English).

This book will teach you advanced vocabulary, phrasal verbs and idioms with excellent examples and constant repetition. Each of the nine chapters ends with written dialogue and exercises to practise and test you on what you have studied in that chapter.

It is designed for self-study, so you don't need a teacher, but it can also be used in the classroom by experienced mother-tongue English speakers.