For two years, Rancid drifted from its goal of generally being, according to its official Web site, "a public nuisance." The punk band that took the Clash's attitude and made it epic abruptly emerged from its hiatus four months ago by launching a worldwide summer tour and promising an album inside a year. Heavy bass leads, ska-centered rhythms and Tim Armstrong's ever-slurred lyrics still distinguish Rancid's music, but starting with 2003's Indestructible, the group began employing zagging electric guitar lines and rough-hewn, haunting harmonies. Among the first to douse other genres in the punk-rock concept, Rancid continues to incorporate reggae, rock and Dylan-evoking ballads with an updated but still beautifully simplified punk sound. Politically charged song topics reveal that Rancid has not forgotten its roots or its charge: to be a gadfly.