Roots of Complex Numbers

Within the context of real numbers, the square root function is well-defined; that is, the function ##f## defined by:
##f(x) = \sqrt{x}##
Refers to the principal root of any real number x.
Is it true that this is not the case when dealing with complex numbers? Does ##\sqrt{z}##, where ##z ∈ ℂ##, represent more than one value?