Part of a series showing 8-12 year-olds how to make working models from household rubbish. Step-by-step drawings and instructions explain how to build the models, and the technology behind them, including the mechanics of pulleys, levers and wheels. Readers are also given ideas for designing their own models. Peter Firmin is the creator of models for a number of TV series, including "The Clangers" and "Bagpuss".