Just a thought: I might consider a different monetization strategy than AdSense. The ads really look awful and make the site seem significantly less 'quality' than it actually is.

I might experiment with some sort of freemium model; maybe for free you could get the first half of sections for every chapter and then you can pay ~$5 to get access to everything.

Or, as someone above mentioned, compile it into an ebook and have that advertised on the site for ~$10, but make the entire website free.