Thunderbolts is a series of leveled reading books covering popular non-fiction topics, with particular appeal to older readers. Each book contains a non-fiction section followed by a fiction story on the same topic. There are four sets in the series. Each set contains six books and is leveled to allow progression. These books are also valuable as starting points for discussion and creative work. The Thunderbolts Library Pack includes all 24 reading books from the series, Set 1 the first six books have no words allowing readers with greatest difficult to engage. Set 2 introduces a limited number of words, and Sets 3 and 4 offer further progression.