Rancid was formed by Tim Armstrong and Matt Freeman, both formally of Operation Ivy a ska/punk outfit.
They recruited Brett Reed on drums and recorded "Rancid" in 1993. Right before "Rancid" was released Lars Fredrikson joined the group as second guitar and vocalist.
And then with this line-up, which has yet to change, the band released "Let's Go". This album scored a mild hit on MTV called "Salvation", and then Rancid became the target of a major label war (including Madonna's Maverick label and Epic), although in the end they stayed with their original label Epitaph, mainly because, as Tim and Lars say, "it was like being in a family and we like that, you know all our friends are there, and it just seemed right". After this bidding war Rancid released "...And out come the wolves" in which Rancid showed the ska that had been in Op Ivy and slowed down the tempo from the last two albums. After several years they made the ska/reggae connection clearer with Life Won't Late, which is a very good album, even if quite a few fans didn't like it.
Then two years later in 2000 Rancid released Rancid(2000) which is a very hardcore, street punk album, which again some fans don't like.
Rancid have moved along very well, always changing, for 4 albums I'd say they've changed alot, and each change has always been very interesting.