In 1978, Jim Pex changed careers and was hired by the Oregon State Police as a state trooper. He transferred into the crime lab and began a career that would last 25 years with them. During this time, he developed a number of innovative and important scientific methods for use by law enforcement. Not all times were good times and he outlines some of the difficulties working within the agency. After retirement, he worked another 15 years as a consultant for the defense. He talks about several actual cases, some high profile, some not, and the scientific procedures required to affect a positive outcome. Most of these cases were death investigations and a few involved people that were falsely accused. Some others, leave the door open for the reader to consider the facts and make their own decision. Jim Pex demonstrates in this book how scientific problems become opportunity and application of elimination theory to scientific method was an important approach to solving crime.