"Rolling Stone" noted the genre's lack of a clear definition. Robert Loss acknowledges the challenges of defining "grunge"; stating that while he can recount stories about grunge, they do not serve to provide a useful definition. Roy Shuker states that the term "obscured a variety of styles." Stetson states that grunge was not a movement, "monolithic musical genre", or a way to react to 1980s-era metal pop; he calls the term a misnomer mostly based on hype. Stetson states that prominent bands considered to be grunge (Nirvana, Pearl Jam, Soundgarden, Alice in Chains, Mudhoney and Hammerbox) all sound different. Mark Yarm, author of "Everybody Loves Our Town: An Oral History of Grunge", pointed out vast differences between grunge bands, with some being punk and others being metal-based.