Without a formal education, what is the quickest way to learn an extended vocabulary?

I would like to extend my education and understanding lies in reading books with words unfamiliar to me. Is there a particular book, magazine subcription or other that will allow me to habituallly grasp more in conversation and reading comprehension. And please don't say the dictionary. Narrow it down to a good vocabulary book or text book that you are familiar with. In the long run I want to learn more in regards to engineering and the big words just throw me.