She's graced with a singular voice, one that soars like an arrow to the heart, but Tracy Chapman is flexible in how she uses it. This is true of her live collaborations—a scorching take on “Give Me One Reason” with Eric Clapton; a Pavarotti-enhanced “Baby, Can I Hold You Tonight”—and of her forays into various genres, like the country-ish drawl of “Woman's Work” and the jazzy bop of “It's OK.”