54 books • 27 series
UFOs (Kingfisher explorer books) (Random House All-About Books) (Random House Picturebacks)
The Violent Earth (Random House All-About Books) (First Look at Nature Books) (Kingfisher explorer books)
The World of Speed (Explorer Books) (Piccolo explorer books) (Kingfisher explorer books)
Knights & Castles (Random House All-About Books) (Kingfisher Colour Books) (Kingfisher explorer books)
Age of Steam (Kingfisher Colour Books) (Random House All-About Books) (Kingfisher explorer books)