Persistent cookies store information on your computer for longer periods of time and across multiple sessions. The Library never uses persistent cookies to collect personal identifiable information about our website visitors. The Library uses persistent cookies to improve our web metrics by distinguishing between new and returning visitors; to prevent repeated prompting to complete our customer satisfaction survey, to anonymously aggregate data on how visitors use our sites and to ""remember"" preferences that you voluntarily provide in order to create a more seamless experience. 