This book, Joe Kaufman's What Makes It Go? What Makes It Work? What Makes It Fly? What Makes It Float? is one of our favorites. I bought it used a few years back after Sadie and I fell in love with it at a local cafe. It was just sitting there in the toy bin and we couldn't believe how great it was. It's got wonderful descriptions and drawings of how things work, like cassette tapes and record players. It's from 1971. Of course, many things work the same way like cars, boats, and dishwashers, so it's completely relevant. And the drawings and graphic style make me so happy. I get so bummed when I see so many new reference guides using only photographs and digital artwork. We have another Joe Kaufman book—a human body one which is outstanding as well. It's got that great Free to Be vibe about our bodies and how they function.