The Hours

With the exception of the opening and final scenes, which depict the 1941 suicide by drowning of Virginia Woolf in the River Ouse, the action takes place within the span of a single day in three different years and alternates between them throughout the film. In 1923, Virginia has begun writing the book Mrs Dalloway in her home in the town of Richmond outside London. In 1951, troubled Los Angeles housewife Laura Brown escapes from her conventional life by reading Mrs Dalloway. In 2001, New Yorker Clarissa Vaughan is the embodiment of the novel's title character, as she spends the day preparing for a party she is hosting in honor of her former lover and friend Richard, a poet and author living with AIDS who is to receive a major literary award. Richard tells Clarissa he has stayed alive for her sake, and the award is meaningless because he didn't get it sooner, until he was on the brink of death. She tells him she believes he would have won the award regardless of his illness. Richard often refers to Clarissa as "Mrs. Dalloway" - her namesake - because she distracts herself from her own life the way the Woolf character does.
Virginia, who has experienced several nervous breakdowns and suffers from bipolar disorder, feels trapped in her home. She is intimidated by servants and constantly under the eye of her husband, Leonard, who has begun a publishing business, Hogarth Press, at home to stay close to her. Virginia both welcomes and dreads an afternoon visit from her sister Vanessa and her children. After their departure, Virginia flees to the railway station, where she is awaiting a train to central London, when Leonard arrives to bring her home. He tells her how he lives in constant fear that she will take her own life. She says she fears it also but argues that if she is to live, she has the right to decide how and where.
Pregnant with her second child, Laura spends her days in her tract home with her young son, Richie. She married her husband, Dan, soon after World War II. On the surface they are living the American Dream, but she is nonetheless deeply unhappy. She and Richie make a cake for Dan's birthday, but it is a disaster. Her neighbor Kitty drops in to ask her if she can feed her dog while she's in the hospital for a procedure. Kitty pretends to be upbeat, but Laura senses her fear and boldly kisses her on the lips; Kitty laughs it off as if it didn't happen. Laura and Richie successfully make another cake and clean up, and then she takes Richie to stay with Mrs. Latch. Richie runs after his mother as she leaves, fearing that she will never come back. Laura checks into a hotel, where she intends to commit suicide. Laura removes several bottles of pills and Mrs. Dalloway from her purse and begins to read it. She drifts off to sleep and dreams the hotel room is flooded. She awakens with a change of heart and caresses her belly. She picks up Richie, and they return home to celebrate Dan's birthday.
Clarissa appears equally worried about Richard's depression and the party she is planning for him. Clarissa, who is bisexual and has been living with Sally Lester for 10 years, had been in a relationship with Richard during their college days. She meets with Richard's ex-lover Louis Waters, who has returned for the festivities. Clarissa's daughter, Julia, comes home to help her prepare. Richard has taken a combination of Xanax and Ritalin and tells Clarissa she is the most beautiful thing he ever had in life, before he commits suicide in front of her. Later that night, Laura, who is Richard's mother, arrives at Clarissa's apartment. It is clear that Laura's abandonment of her family was deeply traumatic for Richard, but Laura reveals it was a better decision for her to leave the family after the birth of her daughter rather than commit suicide. She has led an independent, happier life as a librarian in Canada. She does not apologize for the hurt she caused to her family (Dan and their daughter are also both dead) and suggests that it's not possible to feel regret for something over which she had no choice. She acknowledges that no one will forgive her, but she offers an explanation: "It [her life] was death. I chose life." When Julia visits Laura in her bedroom, she treats her with kindness and sensitivity that Laura does not expect to receive.
The film ends with a voice-over in which Virginia thanks Leonard for loving her: "Always the years between us. Always the years. Always the love. Always the hours."

Question: Why does Laura brown read Mrs Dalloway?
Answer: As an escape from her conventional life.