An encyclopedia is a source of information, usually about a very wide variety of topics. An encyclopedia consists of articles, each on one of the topics. The articles are assigned titles intended to reflect the subjects and contents of the articles. The articles are arranged in the encyclopedia alphabetically by title. Within an encyclopedia any article can refer to another to provide further information about a place, person or thing mentioned in the article. Traditionally encyclopedias were offered in book form; now they are also available on the internet. One excellent example is wikipedia for which a link is given below.
I have a full sent of 1980 enclycopedia plus the childcraft where can I get 3,000 for it?
No, only if the article is a direct quote or contains quotes from people who were present at the occurance or were part of whatever happened.
Whether or not an encyclopedia is reliable and valid depends on the encyclopedia. In the English Language, the Britannica is considered the most reliable general encyclopedia. It uses experts in the field to write its articles. Specialized encyclopedias are frequently valid for the same reason. Frequently, the publisher can be trusted to be accurate. It is possible to check a publisher for the quality of his non fiction. On WikiAnswers a number of the answers have been nonsense. They can not be trusted. Wikipedia has become better over the years. Qualified editors are checking articles and suggested changes for accuracy. Still, its quality and information is not at the point where it is used as an expert witness in court. The quality of an encyclopedia depends on the specialty of the writers of the various writers.