Resumen: A pesar de las apariencias y proclamaciones oficiales, la tolerancia no está hoy de moda. Por ello lo primero que procede es recordar en qué consiste realmente y mostrar cómo es: asistemática, pluriforme, no estrictamente racional, e imprescindible para la vida social. Estudiaremos después la relación que tiene con el Derecho y con los derechos (que no es unívoca), así como los factores ambientales favorables o desfavorables. En cuanto al método, evitamos el razonamiento abstracto y buscamos el histórico y basado en la realidad. Abstract: In spite of appearances and declarations to the contrary, toleration is a not altogether fashionable notion these days. We must, therefore, start by recalling what it really is. Further to that we shall show how it is: unsystematic, taking multiple forms, not strictly rational -- yet utterly essential for the smooth running of social life. We shall consider its relationship with Law as well as with rights, themselves hardly univocal, and liberties. We shall look at elements in today’s environment that are both favourable and unfavourable to it. Our methodology will eschew abstraction and look to historical and concrete approaches that stick close to reality.   Summary: BY WAY OF AN INTRODUCTION. A REMINDER. SOME PROBLEMS CONCERNING TOLERANCE: Tolerance and the Law. Tolerance and Rights.The Paradox of Tolerance. Tolerance and Relativism. Tolerance and Religion. BY WAY OF A CONCLUSION: SOME FACTORS FAVOURING OR HINDERING TOLERANCE. REFERENCES.