Featuring 20 of his hits -- including the 1965 No. 1 for which he is most famous, "The Bridge Washed Out" -- this collection is an excellent introduction to the Nashville-born country singer. "Is It Wrong (For Loving You)" points to the piano-driven country Jerry Lee Lewis resurrected his career with in the mid-'60s, and "Talkin' to the Wall" bears a resemblance to George Jones' early singles. Meanwhile, "The Bridge Washed Out" sounds as much like modern new country as Roger Miller. With such a broad range of styles, one can't help but see the semi-obscure Mack as an underrated talent.