Their previous album having scarcely made a ripple and, now, hitless for two years, the Bee Gees went for a new sound in the hands of producer Arif Mardin. The result was Mr. Natural, the sultriest and most soulful record they had ever delivered up to that time. Shedding their pop sensibilities here and singing in a freer, more soulful idiom (with a strong Philadelphia soul influence) on songs such as "Throw a Penny," and with a funky beat backing them up on a lot of this record, the group is scarcely recognizable in relation to their previous work. Mr. Natural was the liveliest, most invigorating body of music to come from the group since their debut, but it also had moments of extraordinary sensuality, most notably "Charade" and "Had a Lot of Love Last Night." In between those two bookends were the beginnings of the sound that would reach maturity on Main Course, the Saturday Night Fever soundtrack, and Children of the World. Most of it is extraordinarily lively and upbeat, which was also a major change for the group; there are still some ballads here in their old style, such as "Down the Road" (which includes the extensive use of a Mellotron), but even these have a subtlety and freshness that had been lacking in the group's work since their debut. The main virtue throughout is, of course, the singing, which is some of the finest that all three Gibb brothers had ever turned in on a single LP up, mated to some of their loveliest and liveliest songs. Mr. Natural generated no hits, but it was their best original album since Odessa (though also very different from that progressive-oriented double LP.