Following the publication of the first edition of this book, I wrote (or co-wrote) nine additional columns for Optics & Photonics News (OPN), which appeared between April 2001 and April 2007. Some of these columns were included in the Japanese enlarged edition of the book, published in 2006; all nine columns are now included in this second English edition. Throughout the years, I also wrote four columns which were not submitted to OPN, because they ended up being somewhat lengthy and perhaps too mathematical for the general readership of the OPN; these appear here for the first time as Chapters 9, 14, 18, and 25.

The selection of topics and the exposition style of the thirteen new chapters of the present edition follow the same principles and guidelines as did the original thirty-seven chapters of the first edition. In each case a topic is chosen either for its intrinsic value as a foundational contribution to the science of optics (e.g., the Sagnac effect, second-order coherence, the Doppler shift), or because of its technological significance (e.g., optical pulse compression, semiconductor diode lasers, diffractive optical elements). To a large extent, the fifty chapters of the present book are independent of each other and can be read in any desired sequence. Occasionally, when the information in one chapter could benefit the understanding of the material in another, cross references are provided. The presentation style is pedagogic and informal, with mathematics used sparingly unless it is deemed essential and unavoidable.