EN
We give a concise exposition of the basic theory of $H^{∞}$ functional calculus for N-tuples of sectorial or bisectorial operators, with respect to operator-valued functions; moreover we restate and prove in our setting a result of N. Kalton and L. Weis about the boundedness of the operator $f(T₁,...,T_{N})$ when f is an R-bounded operator-valued holomorphic function.