A serializable object is one that can be converted into a string of characters and recreated by reading that string back. Almost all objects in Mathematica are serializable--expressions, programs, graphics, typeset mathematics, user interface elements, even complete notebooks. That's because all these Mathematica objects are represented in a uniform way by symbolic expressions; and, being represented in a textual form, symbolic expressions are serializable.

Most aspects of Mathematica have been serializable since its introduction in 1988, although the concept was not widely used until it was later implemented in Mathematica for Java and C#. Because objects are serializable, MathLink can transmit them to other Mathematica processes--the basis of gridMathematica.