Approx. 340 e-books in English on the subject areas of optics and photonics in the portal of the SPIE Digital Library.
Help and Tutorials:
In principle, it is prohibited to systematically download or print entire e-books or large parts thereof. You may save or print individual pages or chapters for both your personal use and research purposes. E-books must not be passed on to third parties in either electronic or printed form.
Licensing terms for the SPIE Digital Library offer.