These readings are cultural, to help you develop some perspective on the role of functional languages and functional programming in real-world software development. Many of the articles refer to Lisp, a close cousin of Scheme.
An article by Paul Graham describing how and why he (and a colleague) used Lisp to write the software for what is (now) Yahoo! Store.
Paul Graham's site has number of other articles discussing advantages of using Lisp in programming projects.
Common LISP's role in planning parts of the pathfinder mission
Successful Scheme, an article from Unix Insider about Scheme and some of its real-world uses.
The Functional Programming in the Real World website, with pointers to a slew of real-world projects that use functional languages.
Some of the software for NASA's Deep Space 1 was written in LISP.
Schemers.org, the online home for all things Scheme.