Rock music encompasses five decades of music. Traditionally the genre was birthed almost simultaneously between the UK and America. Rock has had wide appeal among younger audiences. The birth of rock and roll is typically believed to have occurred during the mid to late 50s. Elvis Presley and Jerry Lee Lewis were defined as early innovators. Their signature sounds borrowed generously from gospel, soul and R&B.
In Britain another momentous event birthed British rock: the Beatles. When the Beatles first appeared on American soil they led a regular parade of other UK rockers who as a whole have been called the British Invasion. From this musical diaspora came such classic rock bands as The Who, The Rolling Stones and The Yardbirds. Their style caught on with Americans who recognized their homage to the American blues and jazz movements.
Since this initial meeting of American and British rock subsequent litters of rock sub-genres have been spawned. Hard rock and metal were the first to morph from the early rockers. Bands like Led Zeppelin, Van Halen and Metallica all range from these styles. The music relied more heavily on aggressive guitars, usually at least two. Distortion was not unusual and lyrics were screamed and yelled as opposed to sung. On stage, metal, glam and hair bands were renowned for their theatrics. Most notable is Kiss.
Grunge and punk rock defined the late 80s and early 90s. Pearl Jam and Nirvana led the pack of Seattle acts that made rock a more raw, boiled down style laced with a next gen angst and disillusion. Punkers Green Day and Circle Jerks punched up the instrumentals, eliminated jam sessions and underscored the mental torment they found in their native suburbia.
Alternative rock was a sub-genre widely ascribed to a variable assortment of breakaway rock bands later in the 90s and into the new millennium. Really many alternative rock artists tend to fall into more granular sub-genres, such as post-punk, nu metal, grunge rock, thrash rock, garage rock, indie rock, and emo.
Red Hot Chili Peppers and Linkin Park are examples of nu metal. They include features of hip-hop and rap. Female rocker Alanis Morrisette is best described as post-grunge and Avril Lavigne as pop rock. Current post-punk includes the White Stripes and Franz Ferdinand.