In his inaugural lecture to the tenth study session of the International Institute of Human Rights in 1979, Karel Vasak presented a brief but systematic theory of what he called 'the third generation of human rights.' The first generation of human rights included primarily those defined in the International Covenant on Civil and Political Rights (ICCPR). The second generation consisted mainly of the human rights specified in the International Covenant on Economic, Social and Cultural Rights (ICESCR). Although no third covenant was under consideration until 1981, Vasak argued that several new human rights, such as the rights to development, to a healthy environment, and to peace, were already beginning to emerge in international law. He suggested that these three generations of human rights corresponded respectively to the three ideals proclaimed in the French revolution: liberty, equality and fraternity. Accordingly, these new human rights should be thought of as solidarity rights. Now is an appropriate time to reflect upon the emergence of the human rights to development, to a healthy environment, and to peace in international law over the past two decades and to consider whether they do, or even should, conform to Vasak's theory. Sections Two and Three of this article explain his theory of solidarity rights more fully and clearly than he did himself. The fourth section will report on the current legal status of these three human rights. Last, in the fifth section, this article gives and briefly defends a critical assessment of the conception of solidarity rights.