Hey there,
This is a pretty straight forward question so my answer is going to be relativity quick, but my favorite book in internet marketing is:
Jab, Jab, Jab, Right Hook - Gary Vaynerchuck
Idk, it's such a good book to read or listen too and it gives such good information on how marketing in the 21st century actually is.
It's not about just using flashy things to get more attention than your competitor which used to work. Now there are so many businesses, especially online, that you need to provide them with a TON of valuable content that really makes an impact on that area for them and once you've done that offer them a full packaged item for a fee.
That's how marketing now works and I love Gary Vaynerchuck as much as I love his book.
Fantastic book, I'd give it go!
Hope this helped
Adam