Need to know what you should read first in a new subject?

In the course of putting together a 'readable history' display I came across this forum thread today. It seems like a great reading resource. It's interesting to browse through but you could also look for suggestions for a particular discipline by using Ctrl+f/Apple f. Not every respondent stuck to the "for laypeople" stipulation, but an impressive fraction of them did. The question that prompted the thread is: What single book is the best introduction to your field for laypeople?

http://ask.metafilter.com/71101/What-single-book-is-the-best-introduction-to-your-field-or-specialization-within-your-field-for-laypeople