Lexis and Westlaw each publish exclusive and unique treatises and other secondary sources.
For example, Lexis publishes one of the leading legal treatises on civil procedure - "Moore's Federal Practice" - while Westlaw publishes another widely-cited and competing treatise - "Federal Practice and Procedure," often known simply as "Wright & Miller."
You can find these treatises by searching for them by name in the search boxes on Lexis and Westlaw.
As you are typing, pay attention to the suggestion area below the search box and watch for the name of the treatise you are looking for. Once you see it appear in the suggestion area, simply click on the name of the treatise.