For what it's worth, I agree with Mike L. that in effect a book on wage labor
is "missing" from the Marxian canon, in the sense that issues central to the
logic of capitalist exploitation are left begging. As one might expect, I put
the relevant issues in different language than Mike, but one might see the
overlaps between his concerns and the following:
1) the complementary struggles over the length of the working day and
the level of pay have the aspect of a bargaining problem, in addition
to the political or collective class struggle problem discussed by Marx at the
beginning of Vol I Ch. 10, and the "labor extraction" aspect of the
labor-labor power distinction that has been the focus of much
latter-day Marxist work on that issue.
But the class logic of such bargaining struggles is also tied to the
labor-labor power distinction by the following corollary: the
(explicit and implicit) costs of replacing labor power translate into
potential bargaining power among workers. This power is affected by
such things as the ability of the workers to bargain collectively
(which is in turn affected by capitalists' choice of production
method), the level of unemployment, etc.
2) To the extent that the "value of labor power" is defined to
include such things as depreciation of "human capital" or
intergenerational reproduction of labor power, the market for labor
power has the aspect of a "commons", with all of the obnoxious
implications traditionally associated with that arrangement. E.g, an
*individual* capitalist has reduced incentive to pay the "value of
labor power" as defined above to the extent that the capitalist can
replace a "worn-out" worker with a new one fresh off the market.
Clearly the degree of this problem is determined by the size of the
industrial reserve army. This makes the traditional notion of "value
of labor power" problematic at best: a modern illustration of this
is the willingness of US capitalism to underfund public education
drastically.
3) In early or emergent capitalism, the "value of labor power" as
traditionally understood is to some extent supported by the existence
of a peasant, artisan, or other small-holding class. Once the
process of capitalist development has wiped out this class, a
two-fold mechanism takes its place: the underground economy and
welfare (the dole). The latter have a much different, much more
fundamentally political, logic of operation.
4) An issue of central importance which Marx might have addressed in
the missing book is the contribution of capitalism to patriarchy, via
the pressures placed by the former on the family.
Etc, etc. As Mike insists, the bottom line is that issues central to
the logic of capitalist exploitation and development are left
untreated in the absence of the missing "book." Gil Skillman