AGE of the Book
Is it outdated?
Why waste your time using information that is too old for your needs?
If you understand your topic, you'll likely have an idea of what date range your information should fall in.
The right age depends on your topic. For example, if you are writing a paper on the Oregon Trail, a book from 1910 might be appropriate. If your topic is global warming, you should probably not use anything more than 5 years old (unless you're researching the history of global warming, in which case you may want to incorporate an older book along with newer ones.) As a rule, medical books are outdated in five years. When in doubt, ask your instructor or librarian.
You may find two dates: a copyright date and a publication date. Sometimes a book may be re-published for several years, but the information does not change. In these cases, use your best judgment to determine if the information is up to date for your needs.
If you have the book in hand, look for the date on the back of the title page:
You'll also find the date in the library's book catalog:
And here's where you find the copyright date in the Google Books record (The slightly different date is common with revised texts.):