An electronic book (also called an E-book or ebook) is a book in digital form. E-books can be read on a computer or on an electronic reader (e.g., iPad, Kindle). There are many advantages, including the ability to download a book immediately and easily search for information without turning page after page. More free e-books become available on the Internet every day. Here's a site which lists 4000 free books or journals on the topic of Irish, Irish-American, Irish-Canadian and Irish-Australian genealogy: http://freeirishgenebooks.blogspot.com/. Many of these books are out-of-print, rare or otherwise unavailable in paper print. Some were printed in small numbers for private circulation but are now available to anyone online. A quick way to search is to use Ctrl + f (Windows) or Command + f (Mac). I have no personal experience with this site, but it looks like it might expedite the search for "a needle in a haystack."