Dr. Russell Ackoff's short lecture is one of the best descriptions of Systems Thinking. Some notable quotes:
"Sacrificing the parts for the performance of the whole, is a consequence of systems thinking."
"Performance of the system depends on how the parts interact, never on how they act when taken separately."
We deal all the time with engineering teams trying to take all the best parts from cars to make the best car. The key to good design and successful products is a function of Systems Thinking; knowing where and when to make trade-offs without sacrificing “the whole.” Knowing how to think of the System as a whole is also the key to delivering products on time.