Ὁ Κατάσκοπος is different than most of the “easy Greek” out there. It’s not a graded reader; it doesn’t really start easy and get harder as you go. Instead, it keeps the vocabulary easy the whole time and lets the syntax be as hard as it needs to be the whole time. I wish we had more books like this. Most graded readers wait so long to introduce anything remotely complicated—even the future, much less the optative!—that it’s impossible to get any volume with it.