There are five requirements for a person or company to claim ownership to copyright work. These can be stated in simple terms. Issues arise in their application to specific fact situations.
Copyright was orginally applied to "literary works" which by their nature had an element of creativity. Over time a very wide range of mundane work attracted copyright protection. Courts came to recognise the existence of copyright in phone directories, tickets, football league tables and other pedestrian materials.
Firstly in the United States, and now in Australia, the highest courts have heralded a shift back to original principles for literary works.
The shift in the United States was in the U.S. Supreme Court Feist decision which struck down a claim to copyright in a telephone directory. It was felt that the directory was merely a collection of mundane facts involving labour certainly, but not much in the way of creativity.
The shift in Australia began in earnest in the 2009 IceTV Australian High Court decision. In IceTV Pty Limited v Nine Network Australia Pty Ltd  HCA 14, a claim to copyright in a TV guide was dismissed, permitting IceTV to offer its electronic version free of copyright infringement claims.
The case has continuing ramifications for two of the requirements for copyright to exist in a literary work - "originality" and "authorship".
For copyright to exist a work must be original. This requirement is not as high as any need for the work to be unique, especially creative, groundbreaking or even good. However, the work must certainly have some element of creativity and it must not be a copy of someone else's work.
For copyright to exist a work must have an identifiable author or authors. For copyright purposes programmers, artists, creators, architects, photographers and producers are all treated as authors.
The most recent Australian case considering these two requirements was Primary Health Care Limited v Commissioner of Taxation  FCA 419 (4 May 2010). The court struck down a claim to copyright in health records, such as prescriptions and patient health summaries. The court's reasoning is in line with the IceTV decision as regards the originality and authorship requirements. This was supported by the court's observation that the claimed records and notes were found to be dictated by their nature and function.
Another key precedent for the Primary Health Care decision was the significant 2010 decision which found against Telstra's copyright claims to the White Pages and the Yellow Pages. This was the case of Telstra Corporation Limited v Phone Directories Company Pty Ltd  FCA 44.
So what are the five requirements for copyright to be recognised in a work?
Ideas/Expression Dicotomy - This is often referred to as the "first principle of copyright". Copyright protects the expression of an idea, not the idea itself.
Authorship - For copyright to exist a work must have an identifiable author or authors.
Material Form - As copyright protects an expression (not an idea) it must be embodied in a "material form". This includes on such physical things (paper, textiles, sound recordings devices etc) but also extends to computer code recorded in electronic media.
Work - There must be subject matter, eg a literary, artistic, dramatic or musical work.
Original - The work must be original, as discussed above.