If you are asking about the book "Alco FAs, Running in the Shadow", by R. Craig Rutherford (and published by Four Ways West) I've met the author and can assure you that he has indeed "laid a hand on the actual item". The book covers not only the FA-1s, but also the FA-2s and the FPA-4s.
I had a chance to borrow a copy of the book for a few days, and was pretty impressed with the amount of research that went into it's production. There are lots of interesting photos, both inside and out. I spotted a few technical things not quite right, like the mention of the turbocharged EMDs that the FAs competed against when new. There is also a misunderstanding of the difference between the 244 and 251 engine mountings; the author alludes to a difference in the 564 and 581 generator mountings instead.
Overall, though, I thought the book was well done, and I disagree with NRECer's statement that the subject is overworked. The only other book that I can think of that is strictly Alco cab units is Olmstead's (?) "An Acquaintnece With Alco", from many years ago.