FOREWORD: In the early years, the Illuminating Engineering Society, founded in 1906, waited 41 years before issuing the first edition of the Handbook. Technical information was not lacking but the preferred method of publication were Transactions of the Society, not as widely disseminated or conveniently available to as broad an interested audience as a Handbook. Between the 1st edition in 1947 and this 10th Edition there have been revisions in 1952, 1959, 1966, 1972, 1981, 1984 (partial), 1987 (partial), 1993, and 2000.

In each book an ever-broadening range of technologies, procedures, and design issues has been addressed to ensure that the Handbook is the principal source for lighting knowledge. The emphasis in each edition has changed to reflect current application trends and needs of the many and varied readership. Some editions placed more importance on quantitative issues; in more recent years, quality earned important recognition.

The Tenth Edition Handbook has taken cognizance of several issues that impact designs of today: energy limits, the spectral effects of light on perception and visual performance, and the need for flexibility in an illumination determination procedure that takes into account factors such as observer age, task reflectance, and task importance in its illumination determination procedure. This book will return to a more "analytical" approach to recommendations and allow the individual committees' publications, such as Recommended Practices, Design Guides, and Technical Memoranda to fully address appropriate and specific design details for a given application.

The professional editorial team brought talent and discipline to the project. This was not a simple revision to an existing book but an entirely new approach. David DiLaura, Kevin Houser, Richard Mistrick, and Gary Steffy have earned our appreciation for their contributions in developing new material, editing, and designing the overall appearance of the book.

The Lighting Handbook represents the most important reference document in the lighting profession. It is one by which the Society accomplishes its mission: To improve the lighted environment by bringing together those with lighting knowledge and by translating that knowledge into actions that benefit the public. We hope that you, the reader, will find the Tenth Edition your principal reference source for lighting information.