I bought this book in 1987 (Fourth Edition 1986) as it was the prescribed textbook for my undergraduate control systems course. At the time, I found it to be one of the worst quality textbooks I owned. I had the need to brush up on some control theory a few days ago and dug this book out thinking that it probably wasn't as bad as I thought all those years ago and my inexperience at the time was likely the biggest issue. Unfortunately in this case I must admit, this book is terrible. I noticed this book is still available whilst shopping for a decent control systems text! I read the reviews out of curiosity and was surprised to see my sentiments being echoed after thirty years. I find it even more surprising that it is still being recommended as a prescribed book. I find it hard to believe that any educator with a genuine desire to see their students succeed could prescribe this book. Do yourself a favour, do a bit of research and buy one of the many excellent texts out there, do not waste your money on this book. There are authors who are far more deserving of your support than Richard C. Dorf and his abomination.