You can search it without signing in but all they ask for is an email address. They don't even care about passwords. Great tool from RLG (Research Libraries Group).
"RedLightGreen helps you locate the most important books and other research materials in your area of interest, and find out whether what you need is available at your favorite library. Sign in, and you can format and send citations any way you want: MLA, APA, Chicago, Turabian. Just click - and it's done."