What is the single best book on the Grunfeld to start with?

That wasn't a mouse slip either, I was just blind.

Colour blind?

Piece blind?

Probably a little of both.

+1

This has nothing to do with my question.

We had to read this in high school.  Like most books I was assigned to read in high school, I didn't.

I'll second (third?) Understanding the Grunfeld.

Ok, then I'll fourth it.

I didn't study any Gruenfeld book. I just analyze the Gruenfeld games of former WC Kasparov and GM Svidler.

That's about the best advise for someone with experience level of OP, to explore if like the opening. Then something which explains ideas like Rowson's book, or Yelena Dembo's which built on Rowson's rep to a large extent. 

Also worth bearing in mind that complicated but technical openings like Grunfeld and semi-slav, which is extraordinary popular with low rating players on chess com for some reason, are about the worst openings for beginner level players to start on. Even something like the KID is better because although complicated black is generally hacking towards enemy king.

I have given up the Grunfeld as I could not keep up with the theory. My preferred source was "The Safest Grunfeld" by Alexander Delchev and Evgeni Agrest published in 2011 but there is nothing better that is more recent.

The early worm can protect himself from birds

SO play the grunfeld is best

don't try to catch the bird it will catch u

Books are obsolete, a data base is better.
Study the 5 Grünfeld games played at the Yekaterinburg Candidates' Tournament.

Databases are equally useful to class players as useful are calculus books to second graders.