For the 3rd Edition of this popular, authoritative and respected book, the collection has been completely revised and enlarged, with the addition of around 200 new spectra bringing the total number in the library to around 800. A number of improvements in the layout and design of the collection have been made. Some of these, such as a simpler classification system, clearer headings for the spectra, and the insertion of material indexes at the end of each section have been designed to make the library quicker and easier to use. It is also the case that, whereas the previous two editions were comprised of only four separate sub-libraries, covering the transmission and pyrolysate spectra of both rubber and plastic materials, another major improvement for this edition has been the incorporation of an additional, comprehensive library produced using a single bounce attenuated total reflectance (ATR) accessory. This is a very useful development, as since the publication of the second edition of this library in 1997, this type of ATR technique has acquired a high degree of popularity due to its many attributes, including speed and ease of use, the need for only small amounts of sample, and its virtually non-destructive nature. All the spectra in the collection have been collected and stored at a resolution of 4 cm-1 and are plotted as percentage transmittance against wavenumber. For the transmission and pyrolyate spectra, the wavenumber range shown is 400 to 4000 cm-1, whereas for the single bounce, diamond window ATR spectra the range is 650 to 4000 cm-1. The layout of the spectra has been changed for this edition - within each of the five sub-libraries spectra are listed in alphabetical order according to material type, which is displayed in the main heading above each spectrum. A number of polymer blends are represented in these sub-libraries, and the proportions of the polymers in the blend is also shown in this main heading. There is also a secondary heading for each spectrum, where as much additional information as possible has been provided, e.g., the trade name of the material, its manufacturer, compositional information, (e.g., fillers present), and the method of preparing the sample, (e.g., film cast from chloroform) for the recording of the spectrum. As mentioned above, transmission, pyrolysate and ATR spectra are all present in the library. Two different approaches were used to produce the sample films that were used for the recording of the transmission spectra: hot pressing, and casting from a polymer solution. The pyrolysate spectra of the polymers were recorded from collected pyrolysis condensates. Where necessary, samples for pyrolysate work were cleaned up by an initial solvent extraction step. The spectra for the ATR part of the library were recorded using a single bounce, diamond window ATR accessory. This library represents one of the most comprehensive, independent collections of infrared spectra that are commercially available. Drawing on Rapra's international reputation as a centre of excellence and compiled by polymer analysts for polymer analysts it has proved, since the first edition appeared in 1992, to be of immense value to users from both academia and industry. The many improvements in this edition, particularly the inclusion of an ATR section and the enlargement of the range of polymer blends that are covered, will ensure that this library continues to be a must have acquisition for all those concerned with the analysis of polymers and polymer systems.