An explanatory memorandum (EM) is a brief publication that accompanies a new piece of legislation, defining and explaining the terms and concepts, noteably their intended meaning, in the context of the legislation. An EM can be thought of as a "plain English" version of the act.
Until the last decade or so, EMs accompanied only the bill form of the legislation, not the Act itself. This meant that EMs were available for purchase for a brief period only, whilst the legislation was in Parliament, and not afterwards.
Whereas today almost all new legislation has an EM, the further you go back into the past, the fewer the number of EMs provided. For Commonwealth legislation there is a website - Index to explanatory memoranda 1901–1982 - indicating which pieces of legislation had EMs. It can help you save time hunting for non-existant EMs.
The Library's print holdings of Commonwealth bills and EMs is not quite complete - we received our copies loose, and bound them when money became available. Unfortunately some bills and their EMs went missing in the meantime.
However, both recent and historic bills are progressively becoming available online.
If not available online, send for the volume of bills containing the bill which the EM was attached to. Note that the volumes of bills are bound alphabetically within each year. This means that, when placing your order, you will need to indicate the first letter of the bill, as well as the year, to ensure the right volume is delivered (e.g. 1946 T volume for a taxation bill proposed in 1946).
You will need to consult the bills volumes for the year the Act was passed. The Library's bills for any year are bound alphabetically by the title of the bill, so ask for the volume containing the letter with which the name of the bill you need starts.
Explanatory statements accompany legislative instruments and explain what their purpose is and what each part of the instrument is intended to do. They stand in the same relation to legislative instruments as explanatory memoranda do to bills and acts.