It's alluded to being an energy beam that radiates from the weapon's firing head. Some people didn't like this as they said it was a waste, as they cannot salvage anything. Reeve has identified major influences on the "Mortal Engines Quartet", "Star Wars", "The Lord of the Rings" and others. The first volume, "Mortal Engines", won the 2002 Smarties Prize. "A Darkling Plain" won the 2006 Guardian prize. The "Fever Crumb Series" is a second series of novels set centuries or millennia before the events depicted in the Quartet. The main character is Fever Crumb, a London Engineer who is partially descended from the Scriven, a mutant race of humans. The series also introduced the character Shrike, revealing his origins before he became a Stalker. The Fever Crumb series also visits many of the locations not depicted in the Mortal Engines Quartet. "The Traction Codex" is a fictional reference book set in the world of Mortal Engines, written by Philip Reeve and Jeremy Levett. The Codex has only been published in a digital format, as it was originally available only for the digital version of the Mortal Engines Quartet. The book was later made available as a stand-alone e-book. Reeve has expressed his wishes to publish it in the form of a paper book, with additional illustrations and information, which would finally be realised with the release of "The Illustrated World of Mortal Engines" in November 2018. "Traction City" is a short story written for World Book Day 2011. It details the actions of a policeman in the under tiers of London on the hunt for a stalker. A young Anna Fang explores her early life. This story would later be rewritten as the short story Traction City Blues in the Night Flights compilation of stories released in 2018. "In the Bleak Midwinter" is a short story written online by Philip Reeve and Sarah McIntyre, following the young Hester Shaw and Shrike aboard the town of Twyne. "Night Flights" is a short story collection featuring three short stories about the adventures of Anna Fang. It consists of three short stories: "Frozen Heart", "Traction City Blues", and "Teeth of the Sea". "The Illustrated World of Mortal Engines" is a guide to the world of the Traction Era, expanding on the Traction Codex. Written by Philip Reeve and Jeremy Levett and designed by Jamie Gregory, it features illustrations from a variety of artists.