Machine generated contents note: 1.Problems and their setting -- 1.1.Capitalism -- 1.2.Money, a veil? -- 1.3.Money, a symbol? -- 1.4.Money, a language? -- 2.Clarifications -- 2.1.Language and money -- 2.2.Everyday use of money -- 2.3.Prices and the metric of money -- 2.4.Money as things vs. money as pure information -- 2.5.Money as a social relation? -- 3.Elementary theory -- 3.1.Contingency and interaction -- 3.2.Origins and acceptability of money -- 3.3.Quantitative price determination -- 3.4.Money and uncertainty absorption -- 3.5.Credit -- 3.6.Money, credit and crises -- Conclusion -- Appendix -- A.1.Money and inequality according to econophysics -- A.2.Money and the state.