  We define closed model category structures on different categories connected
to the world of operad algebras over the category C(k) of (unbounded) complexes
of k-modules: on the category of operads, on the category of algebras over a
fixed operad, on the category of modules over a fixed operad algebra. In
Sections 2 - 6 we define the necessary structures and provide some standard
comparison results. In Section 7 we define cotangent complex. In Section 8 we
define a canonical structure of homotopy Lie algebra on the tangent complex.
