Hi,
It's official, i am a cissp

(march 2017)
It took me one year of preparation (3 to 6 hour a day), and 3 weeks full time, because i had to learn English first hhh
In my opinion, only two books are necessary to passed the CISSP exam :
- CISSP (ISC)2 Certified Information Systems Security Professional Official Study
- CISSP Official (ISC)2 Practice Tests
- May be at the first time cybrary videos
And a lot of work, perseverance, and discipline

Good luck !!!