As an HVAC teacher I am constantly seeking new ways to explore and teach this subject, DDC and BAS. With the diversity of this particular topic, the number of manufacturers, it is very hard to know how to approach this subject from the point of view of someone brand new to this topic. I have been studying this stuff for years, and am now using Automated Logic hardware and software to teach this topic (only because that manufacturer donated this equipment and software with the hope of one day paying off and hiring some of my students), anyway, I have forgotten how I began to study this subject, and it's hard to prepare powerpoint presentations from the point of view of a beginner. But I keep trying. If anyone has a website, or even a good intro textbook please let me know...thanks.