Though not the first episode filmed for The Bob Newhart Show's fourth season, "The Longest Good-Bye" was chosen as the season opener on September 13, 1975. Tom Poston makes the first of several appearances as Bob's prankish old college chum Cliff Murdock. Having arrived in Chicago to close a business deal, Cliff moves in "temporarily" with Bob and Emily -- and before long has firmly entrenched himself, virtually taking over the Hartleys' home and lives. "The Longest Good-Bye" was written by Tom Patchett and Jay Tarses.

Howard intrudes upon Bob and Emily's sixth anniversary celebration with another big problem. In love with Bob's sister, Ellen, Howard is too nervous to propose. It is up to Bob himself to pop the question -- and never mind the implications. Also appearing are Richard Balin as Fred Goring, Don Nagel as the waiter, and Verne Rowe as the trumpet player. Written by Gordon and Lynne Farr, "Here's Looking at You, Kid" first aired on September 20, 1975.

Bob's plans to hold a surprise party for his therapy group are messed up by the non-arrival of one patient, Mr. Gianini. Somewhat miffed, Bob exiles Gianini in absentia. Expressing long-withheld hostility towards the missing member, the rest of the group applauds Bob's action, but they quickly change their tune (and the target for their animosity!) when they discover that Gianini has been killed in a freak accident -- buried under a ton of zucchini. Written by Tom Patchett and Jay Tarses, "Death of a Fruitman" originally aired on September 27, 1975.

Emily is convinced that Bob is in a rut. As a result, Emily and Bob switch household responsibilities: She handles the budget while he does the shopping. Bob's misadventure with a grocery-store box boy (Bryan Byers) is a highlight. Written by Gordon and Lynne Farr, "Change Is Gonna Do Me Good" made its first network appearance on October 4, 1975, as the 77th episode of The Bob Newhart Show.

Emily feels that Bob's weight workshop could use a motivational speaker. Pressed into service is Bob's secretary, Carol, who tells her story of how she lost one hundred pounds after graduating "magna cum lard" from high school. Unfortunately, Carol's words result more in perspiration than inspiration. Also appearing are Cliff Osmondas Leonard de Paolo and Marcia Lewis as Louise Gross. First telecast on October 11, 1975, "The Heavyweights" was written by Tom Patchett and Jay Tarses.

Will Mackenzie makes the first of several series appearances as mercurial travel agent Larry Bondurant. The office is abuzz with speculation and trepidation when Carol announces her engagement to a man whom she met on a blind date -- 12 hours earlier. Others in the cast are Robert Casper as Judge Tanner, Pat Cranshaw as the Old Gentleman, and Vince Milana and Ric Mancini as the moving men. Written by Gordon and Lynne Farr, "Carol's Wedding" was the first Bob Newhart Show episode filmed for the 1975-1976 season, but was not shown until October 18, 1975, when the season was already six weeks old.

Bob's participation in a medical foreign-exchange program obliges the Hartleys to play host to arrogant French psychologist Alan Durocher (Rene Auberjonois). Neither Bob nor Emily are quite prepared for Dr. Durocher's "continental" outlook on life. Things come to head when Bob is forced to mediate between the contentious Durocher and his long-suffering mistress, Louise (Francois Ruggieri). Richard Forojny rounds out the guest cast as Artie Berkowitz. Written by Douglas Arango and Phil Doran, "Shrinks Across the Sea" first aired on October 25, 1975.

Feeling that both his life and career are worthless, Bob consults his college mentor, distinguished psychologist Professor Albert (Keenan Wynn). Chuckling at Bob's discomfiture, Albert insists that the "shrink" business is all an elaborate fraud. These soothing words succeed only in making Bob feel more insignificant than ever. Featured in the cast are Tom Fitzsimmons as Webb Franklyn and Bobby Eilbacher as David. Written by Phil Davis, "What's It All About, Albert?" originally aired on November 1, 1975.

Bob is persuaded to appear on a TV interview show hosted by soft-spoken Ruth Corley (Jennifer Warren). But the moment the cameras are turning, Ruth transforms into a barracuda, aggressively attacking both Bob and his profession. Unnerved, Bob is trapped into revealing that he has been treating a prominent local politician -- and then the fur really begins a-flying. Also appearing are Alan Manson as Congressman Avery and Claudette Duffy as Sister Mary Catherine. Written by Bruce Kane, "Who Is Mr. X?" first aired on November 8, 1975.