Book copyrights

From Strix:
I decided to post this here because I didn't feel like registering on some book forum or legal forum for one question. Just a question I have about book copyright dates, if anyone can help me out. In the first couple pages of a book, the dates are usually listed, but I'm never sure what certain ones are for. For example, this book says:
Copyright, 1920, 1931, 1940 by [author name]
Copyright 1949, by [company name]
The very first date is the original publishing date, I think. But the next ones I'm not sure about. Reprint dates? Sorry if this is a silly question...
Unless you want your book to look like one written by a 15-year old high school teen, you should know what you're doing.

Visit http://www.lulu.com/forums/viewforum.php?f=11&sid=d34b545ae83bcb60f9abb86aa0bc6a13 and register yourself as a user.
By the way, after you've published your book, send me one!(even if the title is "Strix teaches you .Net 3.0". :)

Good day,
Xeon.