Here's a perspective on one type of inheritence from outside of the OO mind set. It may give insight into the true nature of inheritence (no delgation though, sorry)
See Rees Re:OO for the source. It's a great article.

Implementation inheritance/reuse - having written one pile of code, a similar pile (e.g. a superset) can be generated in a controlled manner, i.e. the code doesn't have to be copied and edited. A limited and peculiar kind of abstraction. (E.g. Java class inheritance.)

There's also specification inheritence there.

Brad