Over the past 6 years I have taught courses on PLC based control systems. In that time I have been unable to find a controls book that got beyond covering the basic principles. Out of frustration I first made a note set to enhance the existing books. Since then I have been turning it into written chapters, and I am over half way done. You can see the results to date at <A HREF="http://claymore.engineer.gvsu.edu/~jackh/plcbook.html">http://claymore.engineer.gvsu.edu/~jackh/plcbook.html</A> The book is organized so that it encourages hands-on contact with PLCs. The book also focuses on the Allen-Bradley PLC-5 processor. This is because I would rather go deeply into one processor, than lightly brush over all others. Please let me know if you have strong opinions about what should, or shouldn't be in such a book, or you like/don't like something already in the book.