Friendship, Altruism, and Morality, originally published in 1980, gives an account of "altruistic emotions" (compassion, sympathy, concern) and friendship that brings out their moral value. Blum argues that moral theories centered on rationality, universal principle, obligation, and impersonality cannot capture this moral importance. This was one of the first books in contemporary moral philosophy to emphasize the moral significance of emotions, to deal with friendship as a moral phenomenon, and to challenge the rationalism of standard interpretations of Kant, although Blum's "sentimentalism" owes more to Schopenhauer than to Hume. It was a forerunner to care ethics, and feminist ethics more generally; to virtue ethics; and to subsequent influential interpretations of Kant that attempted to room for altruistic emotion and friendship, and other forms of particularism and partialism. In addition, the work has been widely influential in religious studies, political theory, bioethics, and feminist ethics.

Simone Weil philosopher, trade union militant, factory worker developed a penetrating critique of Marxism and a powerful political philosophy which serves an alternative both to liberalism and to Marxism. In A Truer Liberty, originally published in 1989, Blum and Seidler show how Simone Weil 's philosophy sought to place political action on a firmly moral basis. The dignity of the manual worker became the standard for political institutions and movements. Weil criticized Marxism for its confidence in progress and revolution and its attendant illusory belief that history is on the side of the proletariat.
Blum and Seidler relate Weil 's work to influential trends in political philosophy today, from analytic Marxism to central traditions within liberal thought. The authors stress the importance of Weil 's work for understanding liberation theology, Catholic radicalism, and, more generally, social movements against oppression which are closely tied to religion and spirituality.

Simone Weil -- philosopher, trade union militant, factory worker -- developed a penetrating critique of Marxism and a powerful political philosophy which serves an alternative both to liberalism and to Marxism. In A Truer Liberty, originally published in 1989, Blum and Seidler show how Simone Weil's philosophy sought to place political action on a firmly moral basis. The dignity of the manual worker became the standard for political institutions and movements. Weil criticized Marxism for its confidence in progress and revolution and its attendant illusory belief that history is on the side of the proletariat. Blum and Seidler relate Weil's work to influential trends in political philosophy today, from analytic Marxism to central traditions within liberal thought. The authors stress the importance of Weil's work for understanding liberation theology, Catholic radicalism, and, more generally, social movements against oppression which are closely tied to religion and spirituality.

Friendship, Altruism, and Morality, originally published in 1980, gives an account of "altruistic emotions" (compassion, sympathy, concern) and friendship that brings out their moral value. Blum argues that moral theories centered on rationality, universal principle, obligation, and impersonality cannot capture this moral importance. This was one of the first books in contemporary moral philosophy to emphasize the moral significance of emotions, to deal with friendship as a moral phenomenon, and to challenge the rationalism of standard interpretations of Kant, although Blum's "sentimentalism" owes more to Schopenhauer than to Hume. It was a forerunner to care ethics, and feminist ethics more generally; to virtue ethics; and to subsequent influential interpretations of Kant that attempted to room for altruistic emotion and friendship, and other forms of particularism and partialism. In addition, the work has been widely influential in religious studies, political theory, bioethics, and feminist ethics.