Below are a list of books on thermography all of which I recommend, the first three are essential for anyone serious about working in the field of thermography. For other products see our products page.
Infrared Thermal imaging Fundamentals, Research and Applications by Vollmer
Common Sense Approach to Thermal Imaging by Gerald C Holst (essential reading)
Practical Applications of Infrared Sensing and Imaging Equipment by Herbert Kaplan (essential reading)
A Practical Guide to Infra-red Thermography for Building Surveys published by BRE
Building thermography by Davide Lanzoni
Infrared thermography: electrical and industrial by Davide Lanzoni
Infrared Thermography: Errors and Uncertainties by Wiley
The Infrared Handbook by Wolfe & Zissis (essential reference book)