Do you notice any differences between these books?

I decided to post this here as it is related to programming books and this is the programming forum so umm yeah.

I like to learn by reading books and I want to learn PHP so I am going to get a PHP book. I found http://www.amazon.co.uk/gp/product/0672329166/ref=sib_rdr_dp which seems like a good book and its pretty cheap however I also found http://www.amazon.co.uk/PHP-MySQL-Web-Development-3rd/dp/0672326728/ref=sr_1_4?ie=UTF8&s=books&qid=1225302509&sr=8-4.

Now they look like the same books but the first one is the 4th edition and the other one is the third edition, how come the 4th edition is cheaper than the third?

Yeah they're just different editions of the same book , though theres no reasoning behind the prices , you see this a lot on amazon , just buy the newer cheaper edition , and laugh at amazons inability to price things correctly .

Thanks man, just got a little confused over the price issues, dumb Amazon.

In order to make a new edition of a book, they must change at least 10%. This could mean they changed the pictures, or added another half a book. The older edition will be much cheaper.

If you are learning by yourself, just have to make sure the information isn't out-dated. If it's for a class, try to find an ebook (if you want to save on cost), if you can't, then ask the professor if it will work.