My girlfriend wanted to study while she was on the bus and I couldn't find a suitable PDF for mobile viewing or printing so I wrote a script that extracted the contents of the online handbook into two PDF formats - one that works well for viewing on a mobile phone, and another that can be printed on normal paper without wasting ink on headers and manually going through all the pages.
It doesn't let me post links in this forum for some reason so you'll have to search google for my blog called "code index by mike marynowski" and find today's post titled "Ontario Driver's Handbook PDF (Mobile and Regular)".
This thread came up in my results when I tried to search for a driver's handbook PDF so hopefully this will help out some other people in the same boat!
If you're just looking to pass the test, I always tell people to take the practice tests on the apnatoronto.com website. All of my kids passed the first time and anytime a parent asks me, that's where I refer them. (I'm a driving instructor)