Our look is the result of reader comments, our own experimentation, and feedback from distribution channels. Distinctive covers complement our distinctive approach to technical topics, breathing personality and life into potentially dry subjects. The animal on the cover of Web Performance Tuning, Second Edition is a sword-billed hummingbird. There are over 300 species of hummingbird, all found only in the New World. All of these species are easily identifiable by their long, tubular bills and iridescent feathers. The iridescence is a refraction effect that can be seen only when light is shining on the feathers at certain angles. Hummingbirds range in size from the bee hummingbird, which, measuring 2 inches long and weighing less than an ounce, is the smallest of all birds, to the great hummingbird, which measures about 8.5 inches long.

Hummingbirds are so named because of the humming noise made by their rapidly moving wings. On average, hummingbirds flap their wings 50 times a second; some species can flap as many as 200 times per second. The wings are flexible at the shoulder and, unlike most birds, they are propelled on the upstroke as well as the downstroke. Because of this flexibility, hummingbirds can hover, fly right or left, backward, and upside down. Most hummingbirds have tiny feet that are used only for perching, never for walking. Hummingbirds will fly to travel even a few inches.

Hummingbirds expend a great deal of energy, and they need to feed every 10 minutes or so. They feed on nectar, for sugar, and small insects, for protein. Their long, tapered bills enable them to retrieve nectar from even the deepest flower. Pollen accumulates on the head and neck of hummingbirds while they gather nectar. They then transfer this pollen to other flowers and thus play an important role in plant reproduction.

Hummingbirds appear frequently in Native American legends and mythology, often as representatives of the sun. According to some folk beliefs, they can bring love. Since Europeans first spotted these beautiful, colorful little birds, they have often appeared in the art and literature of the Old World, as well. Mary Brady was the production editor and proofreader for Web Performance Tuning, Second Edition. Sarah Jane Shangraw was the copyeditor. Darren Kelly and Claire Cloutier provided quality control. David Chu and Julie Flanagan provided production support. Lucie Haskins wrote the index.

Edie Freedman designed the cover of this book, using a 19th-century engraving from the Dover Pictorial Archive. Emma Colby produced the cover layout with QuarkXPress 4.1, using Adobe's ITC Garamond font.

Melanie Wang designed the interior layout, based on a series design by David Futato. Neil Walls converted the files from Microsoft Word to FrameMaker 5.5.6 using tools created by Mike Sierra. The text font is Linotype Birka; the heading font is Adobe Myriad Condensed; and the code font is LucasFont's TheSans Mono Condensed. The illustrations that appear in the book were produced by Robert Romano and Jessamyn Read using Macromedia FreeHand 9 and Adobe Photoshop 6. The tip and warning icons were drawn by Christopher Bing. This colophon was written by Clairemarie Fisher O'Leary.