It isn't, but the book is well worth getting. Gives a lot of insight , things and tips, especially while you wait to be able to do it and cheaper than a set of quality double butted spokes ;-) http://www.wheelpro.co.uk/wheelbuilding/book.php
I have the Spokeys Pro (Riken Kaul) and the non pro version.
If you buy a pro it should slide on easily sometimes thentwo grab bits can get misaligned when they are made. Where I go mine from they sent a new one out.
Mart also make/rebrand them and use the okn grab version (you'll see what I mean if you search for Spokeys.
Once you get use to them, they are quick to use.
The non pro are easier on warn nipples.
Red is the common size.
But it is down to preference and I have a few other styles that like to use sometimes. Like the cheaper park tools, had that and my original Spokeys since BiTD. But find the cheaper park tools easier to damage nipples with.
I built my wheels with a red spokey, only a couple of quid from rose bikes.
Most of the wheel build can be completed with a screwdriver at the back of the nipple. It is really just the final tensioning and truing where you need the spoke key.