Season 1 (2005):

This season introduced the main characters and general plot line of a documentary crew following the daily lives of the fictitious Dunder Mifflin Paper Company. It shows Micheal Scott, regional manager of the Scranton branch, as he tries to convince the filmmakers of the documentary  that he presides over a happy, well-running office. Meanwhile, sales representative, Jim Halpert  finds methods to undermine his cube-mate, Dwight Schrute. The receptionist, Pam Beesly, is trying to deal with Micheals daily shenanigans. Finally, the temporary employee, Ryan Howard, acts as an observer to the insanity surrounding him.

Season 2 (2005-2006):

The second season further developed into the plot of the fear of company downsizing, along with the introduction of new characters and developing some of the minor one. As Michael starts a relationship with his boss Jan Levenson, Pam and Jim’s relationship become one of the significant points of the season. Their compatibility becomes more obvious as Jim’s feelings for Pam continue to grow, while she struggles with her relationship with the warehouse worker Roy Anderson.

Season 3 (2006-2007):

The season marked the move of main character Jim Halpert from Scranton to Stamford. The main plot for the early episodes of the season deals with the problem of company downsizing and in the last half of the season inter-office relationships becomes significant.

Season 4 (2007-2008):

Relationships emerged as the main theme of the season, with Jim and Pam's rising, and Michael and Jan's, as well as Dwight and Angela's declining.Technology was another theme as the office staff struggled with initiatives introduced by Ryan to modernize the company.

Season 5 (2008-2009):

This season highlighted Michael's roller coaster relationship with corporate, as he is first praised and rewarded for impressive numbers despite the economic downturn. However, when a new boss is hired Michael feels slighted by his controlling manner. The theme of the beginning and middle of the season was mostly personal relationships with Dwight, Angela, Andy, Jim, Pam, Michael, Jan, and Holly. However, the theme transformed into career growth, as Ryan, Pam, and Michael set up the Michael Scott Paper Company, Pam and Michael go on a lecture circuit, Charles takes Jan's and Ryan's job, and Jim has trouble with the new boss, Charles. The last two or so episodes of the season focused on relationships once again, with major events taking place in Jim and Pam's relationship, and also with Holly and Michael.

Season 6 (2009-2010):

The sixth season highlights include Jim becoming co-manager with Michael of the Scranton branch, Michael dating Pam's mother, Dwight attempting to get Jim fired, and Dunder Mifflin facing an uncertain future due to rumors of insolvency, eventually becoming part of a larger corporation called Sabre. The season also prominently features the long-awaited wedding between Jim and Pam, as well as the birth of their first child.

Season 7 (2010-2011):

This season largely revolves departure of Michael from the series. After Toby is called for jury duty, Holly returns, causing Michael to once again pursue her, despite her being in a relationship. After eventually proving himself to her, the two get engaged, but Michael decides to move to Boulder, Colorado to help Holly take care of her elderly parents. After Michael leaves, the office is forced to choose a new manager.

Season 8 (2011-2012):

This is largely centered around the new Sabre CEO, Robert California. As the season progresses, it becomes obvious that his management style is slowly destroying the company. Dwight—along with Jim, Stanley, Ryan, Erin—travel to Florida to help set up a Sabre Store Eventually, former CFO of Dunder Mifflin David Wallace buys back the company, firing California.

Season 9 (2012-2013):

This season focuses on the relationship between Jim and Pam Halpert. After Jim decides to follow his dream and start a sports marketing company in Philadelphia, Pam begins to worry about moving, and the couple's relationship experiences stress. Meanwhile, Andy abandons the office for a three-month boating trip, and eventually quits his job to pursue his dream of becoming a star. Dwight is then promoted to regional manager.