The Pāli word mettā is a multi-significant term meaning loving kindness, friendliness, goodwill, benevolence, fellowship, amity, concord, inoffensiveness and non-violence. The Pāli commentators define mettā as the strong wish for the welfare and happiness of others (parahita-parasukha-karana). Essentially mettā is an altruistic attitude of love and friendliness as distinguished from mere amiability based on self-interest. Through mettā one refuses to be offensive and renounces bitterness, resentment and animosity of every kind, developing instead a mind of friendliness, accommodativeness and benevolence which seeks the well-being and happiness of others. True mettā is devoid of self-interest. It evokes within a warm-hearted feeling of fellowship, sympathy and love, which grows boundless with practice and overcomes all social, religious, racial, political and economic barriers. Mettā is indeed a universal, unselfish and all-embracing love. Mettā makes one a pure font of well-being and safety for others. Just as a mother gives her own life to protect her child, so mettā only gives and never wants anything in return. To promote one's own interest is a primordial motivation of human nature. When this urge is transformed into the desire to promote the interest and happiness of others, not only is the basic urge of self-happiness of others, not only is the basic urge of self-seeking overcome, but the mind becomes universal by identifying its own interest with the interest of all. By making this change one also promotes one's own well-being in the best possible manner. Mettā is the protective and immensely patient attitude of a mother who forbears all difficulties for the sake of her child and ever protects it despite its misbehaviour. Metta is also the attitude of a friend who wants to give one the best to further one's well-being. If these qualities of mettā are sufficiently cultivated through mettā-bhāvanā-the meditation on universal love-the result is the acquisition of a tremendous inner power which preserves, protects and heals both oneself and others.Apart from its higher implications, today mettā is a pragmatic necessity. In a world menaced by all kinds of destructiveness, mettā in deed, word and thought is the only constructive means to bring concord, peace and mutual understanding. Indeed, mettā is the supreme means, for it forms the fundamental tenet of all the higher religions as well as the basis for all benevolent activities intended to promote human well-being.The present booklet aims at exploring various facets of mettā both in theory and in practice. The examination of the doctrinal and ethical side of mettā will proceed through a study of the popular Karanīya Mettā Sutta, the Buddha's "Hymn of Universal Love". In connection with this theme we will also look at several other short texts dealing with mettā. The explanation of mettā-bhāvanā, the meditation on universal love, will give the practical directions for developing this type of contemplation as set forth in the main meditation texts of the Theravāda Buddhist tradition, the Visuddhimagga, the Vimuttimagga and the Patisambhidamagga.