One of the things Mom did on her most recent trip to Spain was to task her local bookshop owner with what turned out to be a 2½ month project: Complete the 10-book collections of Mafalda for both of my sisters and me. Even though they're now out of print, she came through.
Now, if you've never heard of Mafalda, you probably speak English. The comic strip is best known in Europe and Latin America, and features a precocious, political 6-year-old named Mafalda, and her friends. Think Calvin and Hobbes without the tiger, set in Vietnam-era Argentina, with a bit of "Peanuts" mixed in. Mafalda was everywhere when I lived in Costa Rica, a ubiquity similar to Garfield in the U.S. in the 80s. The last book was published before I was even born, but it's a comforting link to the past, and a thorough workout for my Spanish, especially that rare, rusty vos conjugation.
It's a good thing we got several books at once, though... otherwise I might still be waiting to read them!