Two non-Perl books that have been very influential for me are "Zen and the Art of Motorcycle Maintenance", and "Consulting Demons" by Lewis Pinault.
The first book is thought provoking in many areas, but the theme most relevant to programming is the author's meditations on
craftsmanship and quality of work. The reason the title of the book includes "the art of motorcycle maintenance" is that the author uses motorcycles as a metaphor for any object produced by a person or group of people. The author maintains his own motorcycles because mechanics at a shop do a sloppy job because it's just a job to them. To him, the motorcycle is a finely crafted piece of engineering. I think that many Perl programmers (and open source programmers) feel the same way about the difference between software that is the product of careful craftsmanship and that which is the result of the ship-it-because-the-ship-date-is-here mentality.
The book by Pinault is a memoir by a former management consultant who worked at Cap Gemini, BCG, and others. He pulls back the curtain to show the reader the reality of top-tier consulting firms' motivations, culture, and attitude towards clients. He writes from the perspective of having left the consulting field, and thus being able to expose some of the sordid details
of the profession without fear of repercussion.
I think this is a must read for anyone working in the corporate world as the influence of top-tier consulting firms in the world is enormous, and many monks are likely to have to deal with one or another of these organizations during their career. If you are considering a job offer from such a company, Pinault's insights into the pro's and con's of this field would be very useful to you.