Shortly before Batman '89 came out, the Batman brand tie-in cereal had a mail-away offer for all three issues of "The Untold Legend of Batman".
I was like 5. I'd read maybe 2 comics in my entire life by that point and was somewhat indifferent. But I read those three and I've really not stopped since.
Such a great book, with classic art and a fun story that served to introduce myself, and I'm sure dozens others, to Batman. I wish I still had it, but I think I lost the first issue somewhere during one of my many moves :\