Which person and book influence you most? Why?
The most influential books are ones that defined a space and showed how we as engineers, or just humans, create within it. These books transform, rather that just improve, our understanding of a practice.
Dijkstra's Discipline of Programming showed how one could derive a program as one would derive a proof. One could expect to understand a program completely and be sure that it would work. I've found other mechanisms to gain such confidence but they are at root the same mental process. amazon 
Mead and Conway's Introduction to VLSI Systems similarly reduced computer design at the level of transistors to a practice with rules that could be mastered and would provide for unbounded creativity. Cost structures in the industry make the particular style unattractive economically but the physics hasn't changed and the chips would still compute. amazon
Lakoff and Johnson's Metaphors We Live By introduced this aspect of cognitive science which I found directly applicable to my effort to understand and improve the way we use objects. amazon
There were a few books on my mind while I was creating wiki. Although not as permanently profound they have had a strong influence on this particular work.
Leonard Koren's Wabi-Sabi for Artists, Designers, Poets & Philosophers showed to me the lasting value of the impermanent. amazon
Edwin Schlossberg's Interactive Excellence made clear the role of community in defining quality. amazon