The Search/Browse fields, including Title, Author, Period, and Publication, located near the top of many pages serve a dual role.
As information is entered, the various various Cloud fields and any Listing dynamically readjust to reflect the filtering, with e.g. an Author Cloud displaying only those Authors whose names correspond to the letters in the Author field, and the publication Listing filtered by the letters in the Title field.
However, if the Search Button (or ENTER) is pressed, the same information in the fields, plus anything in the Text or extended fields, is used to run a full Search of all the material, and the Search Results displayed. However, in Search Mode, full words are required in the Title, Author, or Publication Fields.
Meanwhile, pressing the [+] to the right of the Search Button displays several additional fields that can be used to filter Searches.