This book represents a comprehensive and detailed display of some of the recent diagnostic methods used in early diagnosis of sepsis especially in neonates. It also comprises a statistical comparison between the diagnostic performance of these methods versus other conventional methods used in routine clinical practice. This is accomplished through an observational case-control study. We tried to reinforce, and sometimes weaken, our findings with the results of other relevant studies in order to offer a rather fair judgmental view about the value of different methods used.