Reserve army of labour is a concept in Karl Marx's critique of political economy. It refers to the unemployed and underemployed in capitalist society. It is synonymous with 'industrial reserve army' or 'relative surplus population', except that the unemployed can be defined as those actually looking for work and that the relative surplus population also includes people unable to work. The use of the word 'army' refers to the workers being conscripted and regimented in the workplace in a hierarchy under the command or authority of the owners of capital. Big industry constantly requires a reserve army of unemployed workers for times of overproduction. The main purpose of the bourgeois in relation to the worker is, of course, to have the commodity labour as cheaply as possible, which is only possible when the supply of this commodity is as large as possible in relation to the demand for it, i.e., when the overpopulation is the greatest. Overpopulation is therefore in the interest of the bourgeoisie, and it gives the workers good advice which it knows to be impossible to carry out. Since capital only increases when it employs workers, the increase of capital involves an increase of the proletariat, and, as we have seen, according to the nature of the relation of capital and labour, the increase of the proletariat must proceed relatively even faster. The above theory, however, which is also expressed as a law of nature, that population grows faster than the means of subsistence, is the more welcome to the bourgeois as it silences his conscience, makes hard-heartedness into a moral duty and the consequences of society into the consequences of nature, and finally gives him the opportunity to watch the destruction of the proletariat by starvation as calmly as any other natural event without bestirring himself, and, on the other hand, to regard the misery of the proletariat as its own fault and to punish it. To be sure, the proletarian can restrain his natural instinct by reason, and so, by moral supervision, halt the law of nature in its injurious course of development.Modern Industry has converted the little workshop of the patriarchal master into the great factory of the industrial capitalist. Masses of labourers, crowded into the factory, are organised like soldiers. As privates of the industrial army they are placed under the command of a perfect hierarchy of officers and sergeants. Not only are they slaves of the bourgeois class, and of the bourgeois State; they are daily and hourly enslaved by the machine, by the overlooker, and, above all, by the individual bourgeois manufacturer himself. The more openly this despotism proclaims gain to be its end and aim, the more petty, the more hateful and the more embittering it is. capitalistic accumulation itself constantly produces, and produces in the direct ratio of its own energy and extent, a relatively redundant population of workers, i.e., a population of greater extent than suffices for the average needs of the valorisation of capital, and therefore a surplus-population... It is the absolute interest of every capitalist to press a given quantity of labour out of a smaller, rather than a greater number of labourers, if the cost is about the same. The more extended the scale of production, the stronger this motive. Its force increases with the accumulation of capital.Taking them as a whole, the general movements of wages are exclusively regulated by the expansion and contraction of the industrial reserve army, and these again correspond to the periodic changes of the industrial cycle. They are, therefore, not determined by the variations of the absolute number of the working population, but by the varying proportions in which the working-class is divided into active and reserve army, by the increase or diminution in the relative amount of the surplus-population, by the extent to which it is now absorbed, now set free. Reserve army of labour is a concept in Karl Marx's critique of political economy. It refers to the unemployed and underemployed in capitalist society. It is synonymous with 'industrial reserve army' or 'relative surplus population', except that the unemployed can be defined as those actually looking for work and that the relative surplus population also includes people unable to work. The use of the word 'army' refers to the workers being conscripted and regimented in the workplace in a hierarchy under the command or authority of the owners of capital. Marx did not invent the term 'reserve army of labour'. It was already being used by Friedrich Engels in his 1845 book The Condition of the Working Class in England. What Marx did was theorize the reserve army of labour as a necessary part of the capitalist organization of work. Prior to what Marx regarded as the start of the capitalist era in human history (i.e. before the 16th century), structural unemployment on a mass scale rarely existed, other than that caused by natural disasters and wars. In ancient societies, all people who could work necessarily had to work, otherwise they would starve; and a slave or a serf by definition could not become 'unemployed'. There was normally very little possibility of 'earning a crust' without working at all, and the usual attitude toward beggars and idlers was harsh. Children began to work already at a very early age. Although the idea of the industrial reserve army of labour is closely associated with Marx, it was already in circulation in the British labour movement by the 1830s. Engels discussed the reserve army of labour before Marx did in Engels's famous book The Condition of the Working Class in England (1845). The first mention of the reserve army of labour in Marx's writing occurs in a manuscript he wrote in 1847, but did not publish: The idea of the labour force as an 'army' occurs also in Part 1 of The Communist Manifesto, written by Marx and Engels in 1848: Marx introduces the concept of the reserve army of labour in chapter 25 of the first volume of Capital: Critique of Political Economy, twenty years later in 1867, stating the following: His argument is that as capitalism develops, the organic composition of capital will increase, which means that the mass of constant capital grows faster than the mass of variable capital. Fewer workers can produce all that is necessary for society's requirements. In addition, capital will become more concentrated and centralized in fewer hands. This being the absolute historical tendency, part of the working population will tend to become surplus to the requirements of capital accumulation over time. Paradoxically, the larger the wealth of society, the larger the industrial reserve army will become. One could add that the larger the wealth of society, the more people it can also support who do not work.