Think and Grow Rich - Written by Napoleon Hill I feel is the "primer" for entrepreneurs.
You want to have an entrepreneurial mindset when you think about starting any kind of business but especially and internet business because this takes much more motivation on your part to stay focused and on task.  This is a must read in my opinion.  You can download a copy here.  Think and Grow Rich

The 7 Great Lies of Network Marketing : Written by Ann Sieg this is a free downloadable ebook (electronic book )that pronounces the myths that have been taught in Network Marketing for many years.  Its a great read all by itself and funny too.  If you are in NWM you may relate.  It is also the "viral" piece that leads to The Renegade Network Marketer E-Book that sells for $67.00.

Adsense Code : Joel Comm aka the "Adsense Guru is the author of this book.  This is the very first book I purchased when I started my website. I found the book easy to read, understand and implement in the first 30 pages.  It requires you to set up an Adsense account and copy and paste html onto your website.  I began generating income within 2 days of putting adsense on my sites.  You can purchase it directly from his site or through Amazon.

Affiliate Millions: Written by Anthony Borelli and Greg Holden I found this to be a very good informational book on what affiliate marketing is as well as very good guides on implementation and driving traffic.  I thought it was a little "Google Advertising" heavy in some parts but does guide you to other forms of advertising which do not depend on Google.  Amazon $16.47.

Multiple Streams of Internet Income: Robert G Allen - While I wouldn't consider this book Advanced marketing there is so much information it could cause you to go into overload.  It discussed everything from his story (which I doubt most of us could pull off) to some very good ways to drive traffic, email marketing, affiliate marketing, joint ventures, etc.  I would pick this one apart and only use the parts that are relevant to what you are doing.  Amazon $16.47.

Super Affiliate Handbook: Rosalind Gardner $47.00 E-book.  This book is all about Affiliate Marketing and presented in a very linear way.  I like the step by step and found it to be clearer than the Affiliate Millions or Multiple Streams of Income books. The methods she teaches aren't all that different but I like the presentation better.

1001 High Traffic Sties to Market your Business for Free: Jinger Jarrett $19.95 E-book.  I love everything Jinger writes.  She has done all the research for you in this book and if you have a webpage, or blog this is a helpful book.  She also includes information on Press Releases and Article Marketing.

The Renegade Network Marketer (ADVANCED MARKETING): The second E-book written by Ann Sieg (newly revised 11/2007)  Cost is $67.00.  This book continues where The 7 Great Lies of Network Marketing leaves off discussing the value of having marketing skills which are not taught in NWM.  One of the bonuses offered is the affiliate system attached to the book which is offered free with purchase.  There is a 90 refund policy.

The Definitive Guide to Google Adwords (ADVANCED MARKETING): Written by Perry Marshall the Google Adwords guru this book will teach you how to use Adwords in your marketing.  My caution with this is that you have the budget to do Adwords before you even look into it.  It is a very competitive and can be costly advertising method.  You can get this as an E-book for $47.00, Expanded Digital with bonus audio's for $97.00, or hardcopy shipped to your for $197.00 with CD's for $197.00.

Google Snatch (ADVANCED MARKETING) : Written by Mohammed Latif.  I "tripped" over this e-book and have never heard of Mohammed but was quite intrigued by his sales letter. The book is not cheap $97.00.  I liken this book to the Renegade in its complexity.  I have a business associate using the system which does require some webpage building knowledge.  Preliminary results are; while time intensive in the set-up it does yield results and is based on sound principals.

GoogleAds For Free (ADVANCED MARKETING) : Though my interest is not really in doing Google Adwords I was so intrigued I purchased this book.  Isn't it something when a title "makes" you do something.  Brilliant marketing.  Here's the gist.  Excellent book, very sound principals but doesn't actually tell you how to get Google Ads for Free (That doesn't surprise you does it??)  This book teaches you .. with excellent guidance how to create one page websites and sell advertising spots to others to generate income so that you can DO Adwords or any other type of advertising you want.  Cost is $47.00 and they have a refund policy.