What are some of the best life-changing books?

Mmmm, beautiful and interesting question Ms. Lina Samer.

However, having filled our family bookcase with more than 3,000 items along 50 years, now I believe that life experience do irreversibly change what we read (not the contrary :) !

However, for avid (and unconventional) readers (of course grown up a in western cultural milieu) I would suggest:

'The Prophet' by Kahlil Gibran, originally published in 1923;

'Zen and the art of motorcycle maintenance 'by Robert Pirsig, originally published in 1974;

'Abu Ali Ibn Sina ou la Route d'Ispahan', by Gilbert Sinoué, originally published in 1989;

'Confessions of an Economic Hit Man', by John Perkins, originally published in 2004;

'To have or to be', by Erich Fromm, originally published in 1976;

'Steps to an ecology of mind', by Gregory Bateson, originally published in 1972.

Hope this helps, but I am anyway available for a so stimulating cultural debate!