Released in January 2001, iTunes was Apple's second "i" application. (The first was the digital video-editing application iMovie.) Like Casady & Greene's SoundJam, iTunes was capable of playing and encoding MP3 files on a Macintosh.

It featured a simple interface that allowed users to turn audio CDs into MP3 files easily, drag and drop songs between the Library (a master list of all the songs on your Mac) and user-created playlists, and record (or burn) customized audio CDs from within the application.

When Apple unveiled the first iPod, it also took the wraps off iTunes 2: an enhanced version of iTunes that, in addition to providing the means for moving music from the Mac to the iPod, introduced a 10-band graphic equalizer (EQ) with 22 presets, a sound enhancer that brings a livelier sound to tunes played in the application, and the ability to fade tracks played in iTunes into one another. (As we go to press, sound enhancement and fades don't transfer to the iPod.)

To accompany its release of new iPod models in July 2002, Apple issued iTunes 3, a Mac OS X-only version of iTunes that included such enhancements as the Sound Check feature, support for playing back Audible.com spoken-word files, the capability to rate songs, and support for Smart Playlistsplaylists you create based on such factors as rating, the number of times you've played a track, and style.

Given Apple's penchant for taking the wraps off a new version of iTunes when it updates the iPod, few were shocked by Apple's tandem announcement of the third-generation iPod and iTunes 4 at a press event in April 2003. This version of iTunes acted as the gateway to Apple's online music emporium, the iTunes Music Store.

It also brought MPEG-4 audio encoding supportin the form of Dolby Laboratories' Advanced Audio Coding (AAC) formatto iTunes. (This format allows you to create smaller, better-sounding audio files than those encoded in MP3 format.) iTunes 4 also let you share music easily on a local network via Apple's OpenTalk (once called Rendezvous) networking technology.

Additionally, the program let you burn archives of your music to DVD, as well as add album artwork to your iTunes Library. And DJs undoubtedly thrilled to the fact that iTunes 4 allowed you to categorize tunes by the number of beats played per minute.

What might have come as a greater surprise to Apple-watchers was the company's October 16, 2003, release of iTunes version 4.1the first version compatible with the Windows operating system. Apple considered this release to be so significant (and out of character) that its ads boldly proclaimed, "Hell Froze Over."

Whether Hades has chilled to that degree is debatable (my understanding is that The Big Freeze must wait until the Chicago Cubs win the World Series), but there's no questioning the significance of this event. It not only opens the doors of the iTunes Music Stores to millions of PC users, but also (finally) brings parity to the Windows iPod.

Before iTunes for Windows, a Windows iPod was a slightly poor relation to its Macintosh cousin. It didn't support the Sound Check feature, let alone browsing by composer, play counts, play dates (a feature that keeps track of recently played songs), or ratings.

Because it was clueless about play dates and ratings, it lacked the ability to use Smart Playlists (a feature I'll look at later in this chapter). And quite frankly, the software that was bundled with the Windows iPodMusicmatch Jukeboxthough serviceable, is not as intuitive as iTunes.

But the days when Windows users had to settle for a second-class iPod are over. Thanks to iTunes for Windows, you'll get the same functionality from an iPod whether you run it under the Mac OS or under Windows.

The one-year anniversary of the iTunes Music StoreApril 28, 2004brought yet another update to iTunes. This update improved the iTunes Music Store by offering user-created mixes (called iMixes), music videos you could watch from within iTunes, free weekly song downloads, and charts of some 1,200 radio stations across the United States.

This update also allowed those with an iTunes Music Store account to play the music they purchased from The Store on up to five registered computers. (Previously, you could play purchased music on up to three registered computers.)

Additionally, Apple reduced the number of copies of a playlist you could burn to a CD from 10 to 7.

And this update included a feature that let those using the Windows version of iTunes convert unprotected Windows Media Audio files (.wma)files incompatible with iTunes and the iPodto Apple's AAC format.

Some iPod owners received direct benefit from this update as well. iTunes 4.5 introduced the Apple Lossless Encoder, a scheme that compresses music files to a little over half their original size while maintaining all their original fidelity.

Thanks to the Apple Lossless Encoder, audiophiles who were unhappy with the compressed formats compatible with the iPodMP3 and AACno longer had to pack their iPods with AIFF and WAV files to get better sound from their music players.

Regrettably, the Apple Lossless Encoder was compatible only with iPods that carried a Dock connector (at that time, third-generation iPods and the iPod mini).

Less than two months later, Apple updated iTunes yet againto version 4.6. This update was designed largely to support Apple's AirPort Express, a wireless 802.11g hub that supports streaming audio from a wireless-networking-equipped computer to your home stereo.

Coincident with the October 2004 announcement of the iPod Photo and iPod Special Edition: U2, Apple updated iTunes to version 4.7. Along with some bug fixes and performance enhancements, this latest version of iTunes included options necessary for moving pictures onto an iPod Photo, added a command for locating duplicate songs, and rejiggered the Preferences window to include a new iPod tab.