Written by an author internationally renowned in the field of molecular spectroscopy, this book provides an up-to-date account of the new experimental and theoretical methods on the high resolution infrared spectroscopy of small molecules. The approach uses a visual approach to spectral analysis, containing large numbers of energy level diagrams and spectra specra to show the progress in identification and line assignment. Covering new and important techniques on laser and Fourier Transform, it also contains both theoretical and experimental chapters. Divided into 3 parts, features covered in the first part include: * Calculations of the vibration-rotation energy levels of rigid and non-rigid molecules * Calculations of the intensities of vibration-rotation transitions * Introduction to linear and non-linear molecular spectroscopy * Use of interferometric and laser spectrometers for measuring infrared spectra The second part presents a detailed treatment of the analysis of the high resolution vibration-rotation spectra of linear, quasilinear, symmetric rotor and asymmetric rotor molecules. In the final part of the book the following topics of current interest are examined in depth: * Electric and magnetic resonance spectroscopy * Spectroscopy of transient species, free radicals and ions, and Van der Waals clusters * Atmospheric and astrophysical spectroscopy, including the spectroscopy of the atmosphere of the Earth and nearby planets, cool stars and molecules in the interstellar medium This comprehensive book is an essential reference for researchers who want to be at the cutting edge in the field of spectroscopy and physical chemistry, atmospheric science and infrared astonomy.