# Preamble

This document aims to describe the purpose, functionality, and implementation of the host for Polkadot's _parachains_
functionality - that is, the software which provides security and advancement for constituent parachains. It is not for
the implementer of a specific parachain but rather for the implementer of the Parachain Host. In practice, this is for
the implementers of Polkadot in general.

There are a number of other documents describing the research in more detail. All referenced documents will be linked
here and should be read alongside this document for the best understanding of the full picture. However, this is the
only document which aims to describe key aspects of Polkadot's particular instantiation of much of that research down to
low-level technical details and software architecture.
