First of all, this is a masterpiece of translation. This illuminates Bresson's famed brevity of expression and clarity of thought. The decisive moment will never be more clearly explained or precisely chronicled.
I have not yet finished the book, but, I hope it contains the following ( which is present in the French Edition "L'imaginaire d'apres nature"); "Le photographie est, pour moi, l'impulsion spontanee d'une attention visuelle perpetuelle, qui saisit l'instant et et son eternite". (Roughly translated, "Photography is, for me, the spontaneous impulse of a perpetual visual attention (attentiveness ???) that captures the moment and its eternity."