This document discusses how to evaluate sources of information. It contrasts library sources, which undergo restricted publication, fact-checking, editing, and revision with peer review, against web sources which may lack these quality controls. It outlines the CRAAP test for evaluating sources based on currency, relevance, authority, accuracy, and purpose. Currency refers to a source's timeliness. Relevance means a source sufficiently covers the research topic. Authority examines a source's author qualifications. Accuracy checks a source's reliability and lack of errors. Purpose determines if a source has bias or hidden agendas. Examples are provided to illustrate applying the CRAAP criteria.