German a cappella group Wise Guys were a most unlikely success story. Not only are a cappella groups a genuine rarity in the 21st century, but the barbershop-style quintet managed to attain remarkable commercial success in the German-language world, selling out concerts and releasing increasingly popular albums. It helped, of course, that the group sang amusing, often humorous pop songs that appropriated aspects of concurrently popular music, from rap and reggae to rock and techno -- all the while singing entirely free of musical instruments. The popularity of the Wise Guys seemed to reach an apex with Radio (2006), a concept album fashioned in the manner of a radio broadcast, including jingles and news bulletins (even a horoscope). Radio peaked at number three on the German album charts, held back from the number one spot only by the Red Hot Chili Peppers and Silbermond; it remained in the Top 100 for 15 weeks -- not bad for an a cappella release. The Wise Guys began in Cologne, Germany, where members Daniel Dickopf, Edzard Hüneke, Marc Sahr, Clemens Tewinkel, and Christoph Tettinger were enrolled as students from 1981 to 1990 at Hildegard von Bingen Gymnasium. Upon graduation, they began pursuing a professional music career and made their recording debut with Dut-Dut-Duah! (1994), which was mostly in English and included some covers (e.g., "Eight Days a Week"). Tettinger left the group in 1995 and was replaced by Ferenc Husta, who made his debut on the next Wise Guys release, Haarige Zeiten (1996), which exhibited a shift toward original German-language material. Thereafter the guys were offered a recording contract with EMI, and they proceeded to record their first album in a professional studio with a genuine producer, Uwe Baltrusch, who would continue to work with...