There is no disputing that Bill Murray (2003's "Lost in Translation") has always been one of the great comedic actors, but in recent years, possibly beginning with 1998's "Rushmore," his career has experienced a rebirth as welcome as it is miraculous. No longer forced to wade through low-rent commercial projects like 1996's forgettable "Larger Than Life" and 1997's "The Man Who Knew Too Little," Murray has foregone the studio system in lieu of working with interesting filmmakers on smaller, more humane projects. Having long since dropped his eager-to-please pretenses, the viewer now gets what they see with Murray: true, realistic, and, yes, sometimes naturally funny characters often hiding a quiet sadness underneath their exterior.

A master of expressing so much with his face without barely having to move a muscle, Bill Murray adds another exquisite performance to his distinguished resumé in "Broken Flowers," written and directed by stridently independent filmmaker Jim Jarmusch (2004's "Coffee and Cigarettes"). A slow-boiling, always absorbing character study posing deceptively as a mystery, the film nonetheless misses its chance at greatness by lacking the cathartic emotional release that the ending practically demands. With a story whose meaning is never spelled out in any certain terms, each individual viewer is led to interpret what they will from it, and what many might find is a whole that is less than the sum of its parts. That leaves the constantly watchable Bill Murray, then, to be the number-one reason why "Broken Flowers" is worth seeking out.

As the unfortunately-named Don Johnston , Murray delivers another class-act performance with what is one of his most reserved and understated roles to date. Even as his part this time demands that he more often than not play reactor to the showier people around him, he stays the irresistible center of attention as the film's focus never drifts from his personal journey. Once considered a Don Juan and now a middle-aged bachelor, Don receives a curious unsigned pink letter in the mail on the same day that his younger girlfriend, Sherry (Julie Delpy), walks out on him. The letter comes from a mystery woman who claims he is the father of her 19-year-old son, a young man who has recently run away to locate his whereabouts. Egged on by friend and neighbor Winston (Jeffrey Wright), Don compiles a list of four women from his past whom he could have possibly conceived a child with (the fifth, he finds, died years ago in a car accident), and then sets out on a cross-country journey to see each of them. What starts out as a means to finding his son gradually turns into something much bigger, as he is forced to confront that the person he once was isn't really any different than the person he now is twenty years later.

"Broken Flowers" is methodically paced but never boring, a subtle (maybe sometimes too subtle) study of a man whose reluctance to change and grow has left him a perpetually lonely person. The trip he takes, and the ex-girlfriends he briefly reunites with, are fascinating even when some of the details are a little vague. For instance, we see Don traveling by airplane to different cities on three or four occasions, but the landscapes in each place stay pretty much the same and there are never any hints concerning the journey's geography. The women, meanwhile, each one only on screen for about ten minutes each, are a diverse lot, some more vividly defined than others.

Sharon Stone (2004's "Catwoman") is a warmer presence than usual as single closet organizer Laura, whose brazenly flirtatious teenage daughter, Lolita (Alexis Dziena), lives up to her name. Next is Frances Conroy (TV's "Six Feet Under," 2004's "The Aviator") as former hippie Dora, one-half of a married real estate agent team whose life in an upper-middle class suburban neighborhood borders on Stepfordesque. Third on Don's list is a wildly funny Jessica Lange (2003's "Big Fish") as Carmen, once an aspiring lawyer and now a kooky, pretentious animal communicator, her every move lorded over by a pushy assistant (Chloe Sevigny). When Don presses her to go with him to have a drink, Carmen politely tells him she doesn't drink. "Well, how about a bite to eat?" he asks. Her reply (and the movie's best line): "I don't...eat." His last visit is to Tilda Swinton's (2005's "Constantine") backwoods white trash Penny, who is up at arms the second she recognizes who has come to see her.

While each of these vignettes work well as individual entities, a little more time afforded to each one might have helped to bring further insight into what each of their relationships with Don really were like. And, despite each stop dropping hints as to who the letter-writer might be (a typewriter at one home, a basketball hoop at another, pink colors matching that of the paper sprinkled throughout each of them), the rooting mystery that initially takes Don to the road proves to be a red herring in and of itself. Without giving away the end, it should be said that there is no clear-cut, tidy conclusion to be found, instead suggesting through a stunted key meeting he has with a teenage boy (Mark Webber) who may or may not be his son that Don must try to let go of his past actions and mistakes before he can ever hope to move forward in his life. The aspirations and hopes he has for a relationship with this grown son are unrealistic and likely unreachable, nothing more than wishful thinking.

The way writer-director Jim Jarmusch handles these ideas in the final pivotal scenes are effective, but not especially satisfying. In essence, they are missing that extra dramatic push before the end credits that the character of Don deserves, his emotions remaining bottled up just as they should have finally been released. 2002's kind of similar, vastly superior "About Schmidt," which also involved a key letter and starred Jack Nicholson as a man who sets out on a road trip after the sudden shocking death of his wife, offered that necessary final moment of heartbreaking purgation that this one sorely lacks.

Attractively shot in a straightforward manner that works well with the low-key tone of the story and for the most part beautifully written, "Broken Flowers" is an auspicious soul-searching dramedy with the ambition to be a greater film than it all adds up as. Bill Murray's superb, almost silently poignant turn, however, invites audiences from the very beginning to genuinely like and care about Don's fate. It is easy to stick with him even as the film's plot developments sporadically frustrate in their vague answers and questionably thought-out open-endedness. "Broken Flowers" may hit some rough patches as it wraps itself up, but at its core is a film that is gentle and wise and thought-provoking.