A licence of copyright is the grant to a third party to exercise some or all of the exclusive rights to do some or all of the exclusive acts granted by copyright. A licence may be exclusive (no-one other than the licensee may exercise the rights), non-exclusive (the licensor may license the same rights to many licensees) or sole (the licensor may exercise the rights in addition to one licensee). National rules will dictate the formalities required., for example who has to sign the licence (whether the licensor and the licensee) and if witnesses are needed.
