The book is a mix of economical and technical aspects of chemical engineering design; so is good for graduates starting the career or for practicing engineer interested in economical aspects of plant design. For me the good companion book for these engineer is "Conceptual design of chemical processes" by J. Douglas or better but out-of-print "Applied Project Engineering and Management" by E. Ludwig.

I never had much use for this text while in school. As with most subjects Senior year, we went too fast to appreciate it. With the years, however, I had cause to appreciate Peters & Timmerhaus. It is packed full of rules-of-thumb for preparations of cost estimates and comparing options. Although it is not the best place to end an economic investigation, it is the best place to start one.

The Fourth Edition is an advancement over the 2nd edition, the one I "grew up" with. Instead of jumping to cost preparation and option selection, then on to preliminary design, it starts out an excellent introduction, basic requirements for OSHA and EPA (including a good section on HAZOPs), a review of computer-aided design, then on to cost preparation and the rest. After option selection, the authors provide a good solid section on process optimization. This is a new area in the text and well worth reading. All in all, a current, concise design book, ideal for the student or the old hand.