FAQ 27.15 Should the inheritance graph of C hierarchies be monolithic or a forest?

FAQ 27.15 Should the inheritance graph of C++ hierarchies be monolithic or a forest?

The inheritance graph should be a forest.

The inheritance hierarchy of well-designed C++ software is normally a forest of little trees rather than a large, monolithic tree. Monolithic trees usually result in excessive use of downcasting. The type-safe philosophy espoused in this book discourages the use of downcasting.