The series' most prolific contributor, Tony Barwick, constantly used tongue-in-cheek aliases whenever he wrote a different episode, calling himself, for instance, "Anne Teakstein," and "Felix Catstein." (He was not alone in this; Donald James wrote the episodes "From Here To Infinity" and "The Sporilla" under the names "Katz Stein" and "Leo Pardstein" respectively.) The only episodes of the series "not" credited to pseudonyms ending in "-stein" are "The Midas Touch," scripted by Trevor Lansdowne and Tony Barwick, the latter billed under his real name for the only time on the series, and the two-part opener "Expect The Unexpected," written by Gerry Anderson.