No it doesn't. Looks like it's been removed because of the pending second edition, which will no longer be free.
Maybe the author changed something. But when I saw the link, I put in $0 and my email and I received a PDF download link.
As much as I appreciate the author's effort, if I have to enter my email to get the "free" book, then the book is not free.
Lots of free things require identifying yourself, like healthcare.
Those, just like this free book, are still free.
Healthcare has expectations of privacy, legally enforceable. Random insert-email-here has expectations of a scale of getting spammed to getting fucked out of your online identity.
"If I have to enter my email to get the 'free' book, then the book is not free" was the original assertion. I missed the implied footnote about privacy expectations.
You pay, personal information and lost time is the currency.
"If I have to show my card to get into Costco, the free samples aren't free"