Abstract. Using a new lemma indicated by the title, and a recent measure preserving version of Lusin's Theorem, we prove the following theorem: Any isomorphism-invariant measure theoretic property which is "typical" for automorphisms of a kebesgue space is also "typical" for Lebesgue measure preserving homeomorphisms of the unit cube I n, n > 2. We also prove a partial converse of this theorem. Taken together, these results clarify the relationship between pairs of theorems proved by several authors, which established the "typicality" of specific properties (such as ergodicity and weak mixing) separately in the measurable and continuous cases.The determination of typical, or generic, properties of measure preserving transformations has proceeded at different paces but with eventually the same results in the measurable (i) and continuous (ii) contexts. For example, it is known for both (i) automorphisms of a Lebesgue space, and (ii) measure preserving homeomorphisms of a compact manifold, that ergodicity, weak mixing and zero entropy are typical. [By "typical" we mean dense G a in an appropriate space.) In this paper we explain the striking similarity of the "typicality" results which have been established separately in the above two contexts, in the following pairs: ergodicity [5,13], weak mixing [6,9], and other properties in [8,9] and [6,3]. We do this by proving the following result [Theorem 6) under the assumption I that the underlying manifold has the fixed point property: Any isomorphism-invariant measure theoretic property which is typical for automorphisms o/ a Lehesgue space is typical for measure preserving homeomorphisms. We also prove [Theorem 5) a partial converse of this result.As a basic tool in the comparison of the measurable and continuous contexts, we use a measure preserving version of Lusin's Theorem developed in a previous paper [3]. That result (Theorem 1 of this paper) is in turn based on a similar theorem due to J.C.