As we were getting ready for a family trip to Jamaica, I was running around Target trying to get odds and ends for the trip. Knowing we would have a few long airplane rides, I checked out the activity books and decided to try a couple Kumon books.
Even before we left, A (age 4.5) found the maze book and sat in his room before bed tracing the paths with his finger. He loves it!
For people who have not seen activity books in years, it's a nice surprise to see the vivid color artwork. The pages are very attractive.
I recommend the Kumon maze books for preschoolers.
Edited to add: Exploring what's out there, I see other maze books and connect the dot books that also have nice colors that are by other publishers too. In the past I have printed connect the dots puzzles from free online sources, but I like the color illustrations and ease of a book format for organization too.