A/HRC/RES/21/15 25. Recommends that a human rights and transitional justice perspective be taken into account in peace negotiations, and that those conducting peace negotiations draw upon the relevant human rights and transitional justice expertise available within the United Nations system; 26. Welcomes the report of the Special Rapporteur on the promotion of truth, justice, reparation and guarantees of non-recurrence,10 in which the Special Rapporteur concluded that, as a set of measures, the four components of his mandate are interrelated and mutually reinforcing when implemented to redress gross violations of human rights and serious violations of international humanitarian law and that, with respect to the meaningful participation of victims, the participatory procedures necessary to address the different needs and opportunities of women, men and children have yet to be established; 27. Acknowledges the fundamental importance of human rights education and training in contributing to the promotion, protection and effective realization of all human rights, including the area of human rights and transitional justice; 28. Invites States to avail themselves of the expertise and advisory services of the Special Rapporteur on the promotion of truth, justice, reparation and guarantees of nonrecurrence in the area of human rights and transitional justice, and encourages the Special Rapporteur, within his mandate, to share experience and information relating to good practices, technical assistance and capacity-building in his interaction with States in this regard; 29. Encourages the Special Rapporteur on the promotion of truth, justice, reparations and guarantees of non-recurrence to work, within his mandate, in close cooperation with relevant special procedures of the Human Rights Council and relevant actors within the United Nations system, including the United Nations Entity for Gender Equality and the Empowerment of Women, the Department of Peacekeeping Operations, the Special Representative of the Secretary-General on Sexual Violence in Conflict, the Special Representative of the Secretary-General for Children and Armed Conflict and the Committee on the Elimination of Discrimination against Women, as appropriate, in the fulfilment of the gender-specific dimension of his mandate; 30. Requests the Office of the High Commissioner to continue to enhance its leading role within the United Nations, including with regard to conceptual and analytical work regarding transitional justice, and to assist States, with their consent, to design, establish and implement transitional justice mechanisms from a human rights perspective, while stressing the importance of close cooperation between the Office of the High Commissioner and the Special Rapporteur on the promotion of truth, justice, reparations and guarantees of non-recurrence, as well as with other relevant actors of the United Nations and other international and non-governmental organizations, with regard to incorporating human rights and best practices into the development and implementation of transitional justice mechanisms and to the ongoing process of strengthening the United Nations system in the area of the rule of law and transitional justice; 31. Invites other relevant actors of the United Nations system to cooperate fully with the Office of the High Commissioner and the Special Rapporteur on the promotion of truth, justice, reparations and guarantees of non-recurrence in the area of human rights and transitional justice; 32. Requests the Office of the High Commissioner to submit an analytical study to the Human Rights Council, prior to its twenty-seventh session, focusing on gender-based 10 6 A/HRC/21/46.