This document discusses dictionaries, including their history and components. It notes that:
1) The oldest known dictionaries were Akkadian empire cuneiform tablets from around 2300 BCE. Samuel Johnson's 1755 English dictionary was a major milestone as the first truly noteworthy English dictionary.
2) Modern dictionaries typically include a pronunciation guide, part of speech, definition, and sometimes examples for each entry. They also have additional reference sections.
3) Dictionaries are useful reference tools for looking up word meanings, translations, spellings, parts of speech, and more. They help expand vocabulary and ensure correct word usage. The reliability of dictionaries also makes them preferable to some online definitions.