Point of view, objectivity, and bias

There is nothing wrong with a source having a point of view, but you should be aware of it so you can consider opposing viewpoints. Biased information can be useful if presented responsibly. You may be want to find opinions if you are preparing a persuasive speech, or to use ideas from well-reasoned arguments in formulating your own arguments. You will also want to be aware of stances that differ from yours so that you can address them in presenting your own position.

Considering reference works:
One of the hallmarks of reference works is that they present a balanced, factual treatment of the various viewpoints and significant issues associated with a topic.

Questions to ask about books:
Is the book objective, or does it appeal to the emotions? Was it written to persuade?Does it present facts, which can be documented, or the author's opinions? Do the facts support the author's viewpoint?