The book gives a broad coverage of the basic elements necessary to understand and carry out research in quantum optics. It presents a variety of theoretical tools and important results for two-level and semiconductor media, many of which could only be found in the original literature of in specialized monographs up to now. The text reveals the close connection between many seemingly unrelated topics. The book "e;Quantum Optics"e; has been written to meet the requirement of the degree and post graduate students. The subject matter has been discussed in such a simple way that the students will find no difficult to understand it. Most of the examples given in the book have been selected from various university examination papers and the book cover the syllabus of almost all the universities.