Fourier Transform Infrared (FTIR) spectroscopy applies the principle that molecular vibrations can absorb infrared radiation in the range of the electromagnetic radiation. This book discusses methods and provides new research on FTIR. Chapter One reviews the advances in the analysis of biological systems by means of FTIR spectroscopy. Chapter Two studies the last advances of infrared spectroscopy applied to the analysis of lignocellulosic materials. Chapter Three presents the Fourier transform infrared spectroscopic, coupled with chemometric tools, to characterize organic matter transformations during the composting process. Chapter Four focuses on applications of FTIR spectroscopy in the wine industry.