"The CIH Exam - Essential Practice Questions by Farcas and Cena is, as the name implies, an essential set of questions in Industrial Hygiene. It is well laid out in 17 sections. The questions are well introduced with a short narrative before the introduction of the pertinent equations and solution to the over 500 example problems. The book serves not only as a formidable preparation for the CIH exam but a good review of basic principles, a reference for many of the day-to-day technical issues confronting the practicing industrial hygienist and a guide for raising awareness of potential problems for which alert action is required. The authors bring a breadth of experience and insight into the issues handled in the text. They bring context to the basic principles to be highlighted by the examples of the questions and their solutions. This should be a must-have text for everyone in the field." Michael McCawley, Ph.D.