At age ten, moved with mother to Pennsylvania after parents' separation; neighbor Oscar Hammerstein II served as mentor

Wrote first amateur musical, "By George" while still in boarding school

Wrote for the CBS TV series, "Topper"

Wrote first musical score, "Saturday Night"; show was optioned for production, but the producer died before funding had been raised; project was shelved until a 1997 production at London's Bridewell Theatre; received a professional recording in 1998

First professional stage work, composed incidental music for "Girls of Summer"

Wrote lyrics to Broadway show, "West Side Story"; adapted into a film in 1961

Only original teleplay produced, "In an Early Winter"

Contributed to the CBS special "The Fabulous 50s"

Wrote lyrics and music for "A Funny Thing Happened on the Way to the Forum"; adapted into a film in 1966

Composed and wrote lyrics for first TV score, "Evening Primrose"

First collaboration with Harold Prince as director, "Company"; recording of the cast album was the subject of D. A. Pennebaker's documentary

Wrote the score for the cult musical "Follies"

With Anthony Perkins, co-wrote first original screenplay, "The Last of Sheila"; directed by Herbert Ross

TV acting debut in a PBS' production of "June Moon"

Composed first original film score, "Stavisky"

First stage revue based on his work, "Side by Side by Sondheim"

Wrote song "I Never Do Anything Twice/The Madam's Song" for the Herbert Ross-directed film "The Seven Per Cent Solution"

Wrote new songs for the Harold Prince directed film adaption of the Tony-winning musical, "A Little Night Music"

Wrote the music and lyrics for the Broadway musical, "Sweeney Todd"; final collaboration with book writer Hugh Wheeler

Last collaboration to date with Prince, "Merrily We Roll Along"

Contributed to the score of Warren Beatty's "Reds"

Stage revue, "Marry Me a Little"; included songs cut from various productions; show assembled by Craig Lucas

First TV adaption of one of his musicals, "Sweeney Todd"; aired on The Entertainment Channel; later rebroadcast on PBS

First collaboration with James Lapine, "Sunday in the Park With George"; received Pulitzer Prize in Drama

An all-star concert version of "Follies" was performed at Lincoln Center; filmed for broadcast on PBS

"Sunday in the Park With George" broadcast on PBS with the original cast

A revised version of "Follies" opened in London's West End with Diana Rigg, Julia McKenzie and Daniel Massey

Second collaboration with Lapine, "Into the Woods"

Provided the song score for Warren Beatty's feature "Dick Tracy"; won Oscar for song "Sooner or Later"

The City Opera production of "A Little Night Music" aired on PBS' "Live From Lincoln Center"

Appointed first visiting professor of drama and musical theater at Oxford University

The controversial musical "Assassins" opened; main characters were all successful or would-be presidental assassins

Second stage revue of Sondheim work, "Putting It Together"; show marked the return to the stage of Julie Andrews

Was subject of tribute, "Sondheim: A Celebration at Carnegie Hall"; filmed for TV and aired in 1993 on PBS

Third collaboration with James Lapine, "Passion"; based on Ettore Scola's 1981 film "Passione d'amore"

Made debut as playwright, co-authoring "Getting Away With Murder" with George Furth

Wrote several songs for Mike Nichols' feature "The Bird Cage"; most songs not used in the final cut

Yet another revised version of "Follies" staged at the Paper Mill Playhouse in New Jersey

Revised version of Off-Broadway revue "Putting It Together" starring Carol Burnett opened in L.A.; production re-staged (with some cast changes) on Broadway

Workshop version of "Wise Guys" staged; directed by Sam Mendes; never transfer to Broadway

Off-Broadway premiere of "Saturday Night" at the Second Stage Theatre

First Broadway revival of "Follies" produced under auspices of Roundabout Theater

The Kennedy Center devoted entire season to works

Broadway revival of "Into the Woods"

Tony award winning Broadway revival of Sondheim's "Assassins"

Broadway revival of "Sunday in the Park with George"