蔣友柏的第4本書『第十九層地獄』是他認為最誠實一本書,10年來在外界的解讀、詮釋與包裝下,蔣友柏的形象與他真實的模樣頗有出入,因此他自己來寫自己〫除了曾經從特權天堂掉入凡間的成長過往、狂妄不成熟的年少時代之外,也有工作的點滴與對設計的想法,在工作與家庭的忙錄縫隙中相當誠實寫下他實際存活的『第十九層地獄』〫Demos Chiang believes his fourth book “Hell Bible” is his most honest writing to date. After over a decade of being studied, interpreted, and packaged by the outside world, Demos Chiang’s image is somewhat different to his genuine identity. Consequently, he decided to write about himself. Besides the process where he was dropped from the prerogative heaven to become a plebian, and his immature, audacious adolescent days, he also writes about his work and thoughts about design. Hell Bible is a genuine account by Demos Chiang about his busy career and family life.