• Who is the author of the information?
• What are the credentials of the author, e.g. qualifications?
• What else did the author publish, especially in the same field?
• Is the author in any way biased?
• Is the information written by a person who is a specialist in this field or is it merely someone's hobby or opinion?
• Is the content verified, reviewed or peer-reviewed in any way?
• If the information is published by an organisation, is that organisation recognised and a reliable source/authority? E.g. the South African National Tuberculosis Association for information on TB-related topics.

Make use of the following resources to answer the above questions:

• Internet. You can do a search for the name of the author to help you determine what else the author has published and might even provide the credentials of the author, etc.
• Publication (book or article). You might find the author's credentials and qualifications in his publications.
• Read the preface!

Definition: Preface "a statement written as an introduction to a literary or other work, typically explaining its scope, intention, method, etc."

(Source: The Collins English Dictionary, 1986:1208)