This site offers the ability to view online the complete text of books, and it also allows you to download them in a variety of format (e.g., pdf) for later viewing on your computer.
The following URL will take you to the page showing the book Biographical and Genealogical history of the city of Newark and Essex county, NJ. http://www.archive.org/details/biographicalgene01newy
By clicking on the book icon that shows on the page you can read the text, or you can download the text in one of six different formats.
You can do a simple or advanced search on several different fields (e.g., author, creator, description, date, etc.). And you can choose to search a variety of different libraries (American, Canadian, etc.)
The site has much more to offer than just books. It also let's you search for audio files, moving images, and software to name a few other options. Keep track of where you are as you move around. You will want to return to the "Text" tab on the menu bar, because that is where the genealogical "pay dirt" is found.