Here are some useful resources for researching history and genealogy:

Digital resources

Google Books
Google has scanned the contents and indexed millions of books. If the book is out of copyright, or the publisher has given Google permission, in Google Books you’ll be able to see a preview of the book, and in some cases the entire text. If it’s in the public domain, you’re free to download a PDF copy.  Each book has a reference page with all kinds of relevant information: book reviews, web references, maps and where you can borrow a copy or buy the book.
HathiTrust is a partnership of academic & research institutions, offering a searchable collection of millions of titles digitized from libraries around the world.  You can read the books online, including through their mobile site.  If you create a login ID,  you can also create collections to store groups of materials.  You may also be able to download a PDF copy but many downloads require that you have a login from one of HathiTrust’s member institutions.

Illinois Digital Newspaper Collections
Since 2005, the History, Philosophy, and Newspaper Library at the University of Illinois has been developing unique digital newspaper content. The works include digital facsimilies of newspapers and trade journals in a variety of fields. The collection contains 45 newspaper titles, 94,803 issues comprising 1,119,781 pages and 7,160,392 articles. You can search, browse, tag, and correct OCR text to improve searchability and access.

Newspaper Archives of the Marshall Public Library
Thanks to the generosity of the Friends of the Library, the newspapers of the Marshall, Illinois Public Library are being digitized and indexed, making them searchable online. Due to the age and quality of the microfilmed copies being digitized, the character recognition of old newspapers is often very spotty, but this is still a tremendous resource. The newspapers are primarily from Marshall and Clark County but include some issues from throughout the state of Illinois, with some dating back to before the Civil War. As of February, 2015, the archives the online collection includes the following newspapers (the date ranges are general; there are often gaps with missing issues):