Tina Fey’s Emmy-lauded 30 Rock is a sharp addition to the smart, neurotic “working girl” archetype established in The Mary Tyler Moore Show or was so memorably inhabited by a raw, wounded Holly Hunter in James L. Brooks’s masterful comedy, Broadcast News. In contrast to the inventive brilliance of Arrested Development or the resonance of The Office, Fey’s sitcom is refreshing for its lack of pretence, in turn epitomising and mocking convention, often with the scorn of a particularly sharp Saturday Night Live parody.

When glib, silver-tongued executive Jack Donaghy (Alec Balwin) takes over the NBC network, he decides to cast unstable comic star Tracey Jordan (Tracey Morgan) as the new star of the sketch program, The Girlie Show. Renamed TGS with Tracy Jordan, Jack’s changes cause friction with executive producer and head writer, Liz Lemon (Fey).

30 Rock usually centres on the standard storylines involving workaholic Lemon’s need to be taken seriously in a man’s world (especially against the glib, yet sympathetic Jack). Even by sitcom standards, Fey is not a great actor, but she does not need to be (after all, she was the show runner and head writer of Saturday Night Live from 1999-2006). Like fellow sitcom star Jerry Seinfeld, Fey recognises the importance of strong performers to compliment her and her writing. If you want to see how this works in reverse, check out non-actor Fey’s blank performance against a haughty Seinfeld in the show’s second season.

The erratic but sweet Jordan heavily features in 30 Rock’s outrageous “B” stories that push sitcom conventions way beyond any kind of reality. Most of the show’s laughs stem from his reckless insecurity (he once bit Dakota Fanning on the face, although Liz concurs that “she kinda deserved it”). Like his obvious inspiration Eddie Murphy, Jordan dons bizarre wigs and heavy make-up in films such as President Homeboy and Death Bank whilst taking NBC page Kenneth under his win: in a recent episode Jordan recruits the cast of ‘80s sitcom Night Court for a final episode in order to curb Kenneth’s mild depression.

The suave, glib Republican Jack Donaghy perfectly serves Alec Baldwin’s wry, mercurial timing, recalling his memorable display of intense, superior machismo in Glengarry Glen Ross. The Oscar-nominated Baldwin effortlessly lifts the quality of the show with his effortless, sharp one-liners and understated delivery.

Even when the subject material is unoriginal (heck, there has even been a “is this because I’m black?” episode), the writing’s cheerful, self-deflating wit lifts the show, in particular its savvy references to pop culture and the current political climate.

A fifth season of 30 Rock has been commissioned for 2010.