We study the graded derivation-based noncommutative differential geometry o
f the Z(2)-graded algebra M(n parallel to m) of complex (n+m)x(n+m)-matrice
s with the "usual block matrix grading" (for n not equal m). Beside the (in
finite-dimensional) algebra of graded forms, the graded Cartan calculus, gr
aded symplectic structure, graded vector bundles, graded connections and cu
rvature are introduced and investigated. In particular we prove the univers
ality of the graded derivation-based first-order differential calculus and
show that M(n\m) is a "noncommutative graded manifold" in a stricter sense:
There is a natural body map and the cohomologies of M(n\m) and its body co
incide (as in the case of ordinary graded manifolds). (C) 1999 American Ins
titute of Physics. [S0022-2488(99)03811-6].