Cambridge Cirtificate in Advanced English 1, 2, 3, 4, 5, 6

Cambridge English: Advanced (CAE), also known as the Certificate in Advanced English (CAE), is an international English language examination developed by Cambridge English Language Assessment (previously known as University of Cambridge ESOL Examinations). It is targeted at Level C1 of the Common European Framework of Reference for Languages (CEFR) and can be used for study, work and immigration purposes.
Here you can freely download the series of CAE books which are, to some extend, helpful for your dream of reaching the C1 Level of the CEFR.

CAE 1: Book + Audio 1 + Audio 2
CAE 2: Book + Audio
CAE 3: Book + Audio
CAE 4: Book + Audio
CAE 5: Book + Audio
CAE 6: Book + Audio