Back in elementary school during our media center days, I can remember always going for an I Spy. Everybody loved these books, man, because 1) you could look at what was basically 100% big, colorful pictures and still say you “read” a book and 2) because despite them being pretty skinny, you could pour over for hours and still fail to find everything listed by the riddles on each page. These things were kind of a reward because you’d check out an actual chapter book like Magic Tree House with words, and then you’d get the I Spy to wash it down. Usually they were all already checked out, but if you were lucky, you could get your hands on one. I can still remember the exact shelf they were on.
I’m pretty sure the Look-Alikes books came after, or at least they started appearing on our library’s shelves long after I Spy already had a hold on me. Plus, if I remember correctly, these ones didn’t have directions or lists of things to look for. So, less fun. They had a different flavor because the objects themselves were used to build the scenes on each page. I guess they were more artsy. Just look, you’ll see what I mean.
And ya can’t forget the Where’s Waldo?s and Magic Eyes. It was this whole genre of picture books that I grew up and fell in love with.