Headway Advanced is suitable for CEFR level C1

Headway is the world's most trusted adult English course. The series' proven methodology, strong grammar focus and integrated skills work give you lessons that really work in class and offers full support at all levels. The Advanced Student's Workbook provides a perfectly-balanced syllabus with extensive resources at all levels for students and teachers.

In depth treatment of grammar.
Integrated skills throughout.
Full support in print, on disc and online iTutor is a digital companion to the Student's Book for students to revise, review and improve their English.

It includes:
Interactive reading, listening and writing practice with instant feedback
Grammar Tutor with audio explanations up to Intermediate level
Language Development at Upper-Intermediate and Advanced covering grammar, vocabulary and spoken English
Printable wordlist with audio for each unitVideo material with interactive exercises.