I have two bookshelves here (don't remember where they came from) and they did not have hardware to secure them. I used a power drill and long steel bolts to take care of that. This is CA, so everything has to be pretty stable, or else. Plenty of stores offer all kinds of brackets and straps.
After northridge i spent the better part of 18 months strapping earthquake waxin every thing down for clients made a nice lil living doing it