(Booklet in French) Monkeys communicate using their most developed senses: mainly sight and hearing, secondarily smell and touch. Visibility is reduced in tropical and equatorial forests where monkeys use sound, the only way of communicating over large distances. The CD includes more than an hours worth of recordings made while tracking monkeys in the forests of Gabon, Cameroon and Zaire, in difficult conditions, often without the animals aware of the recorder's presence.