Black tea does have caffeine, but contrary to popular legend, considerably less of it than coffee. According to this article, an 8 oz cup of brewed coffee can range from 95-100 mg of caffeine (elsewhere I've read 70-150 - I guess it depends on a lot of variables), whereas an 8 oz cup of black tea has 14-61 mg (varies with variety, brewing time, etc.). So if you're used to a giant cup of strong coffee every morning, a cup of black tea may not have enough caffeine for you to really feel it...