One Marine wrote to Smith, "I can't explain the emotional reaction that took place in this dead heart of mine... A surge of confidence has swept through me, and I feel that maybe a fellow has a fighting chance in this world after all.

"[2] The main metaphor of the book is the hardy Tree of Heaven, whose persistent ability to grow and flourish even in the inner city mirrors the protagonist's desire to better herself.

Book One opens in 1912 and introduces 11-year-old Francie Nolan, who lives in the Williamsburg tenement neighborhood of Brooklyn with her 10-year-old brother Cornelius ("Neeley" for short) and their parents, Johnny and Katie.

The family subsists on Katie's wages from cleaning apartment buildings, pennies from the children's junk-selling and odd jobs, and Johnny's irregular earnings as a singing waiter.

Book Two jumps back to 1900 and chronicles the meeting of Johnny and Katie, the American-born teenage children of immigrants from Ireland and Austria, respectively.

During the first seven years of their marriage, the Nolans are forced to move twice within Williamsburg, due to public disgraces caused first by Johnny's drunkenness and later by the children's Aunt Sissy's misguided efforts at babysitting them.

In Book Three, the Nolans settle into their new home, and seven-year-old Francie and six-year-old Neeley begin to attend the squalid, overcrowded public school next door.

Francie works in an artificial flower factory, then gets a better-paying job in a press clipping office after lying about her age.

Although she wants to use her salary to start high school in the fall, Katie decides to send Neeley instead, reasoning that he will only continue learning if he is forced into it, while Francie will find a way to do it on her own.

Once the United States enters World War I in 1917, the clipping office rapidly declines and closes, leaving Francie out of a job.

After she finds work as a teletype operator, she makes a new plan for her education, choosing to skip high school and take summer college-level courses.

She passes with the help of Ben Blake, a friendly and determined high school student, but she fails the college's entrance exams.

A brief encounter with Lee Rhynor, a soldier preparing to ship out to France, leads to heartbreak after he pretends to be in love with Francie, when he is in fact about to get married.

In 1918, Katie accepts a marriage proposal from Michael McShane, a retired police officer who has long admired her and has become a wealthy businessman and politician since leaving the force.

She is about to start classes at the University of Michigan, having passed the entrance exams with Ben's help, and is considering the possibility of a future relationship with him.

Before she leaves the apartment, Francie notices the Tree of Heaven that has grown and re-sprouted in the building's yard despite all efforts to destroy it, seeing in it a metaphor for her family's ability to overcome adversity and thrive.

The story of Francie traces her individual desires, affections, and hostilities while growing up in an aggressive, individualistic, romantic, and ethnic family and neighborhood; more universally it represents the hopes of immigrants in the early twentieth century to rise above poverty through their children, whom they hope will receive "education" and take their place among true Americans.

Katie becomes pregnant just before Johnny dies and survives on her own until she agrees to marry Sergeant Michael McShane, a pipe-smoking local policeman-turned-politician.

Sissy has ten stillborn children, but adopts an immigrant girl's baby daughter born out of wedlock and eventually gives birth to a healthy son of her own.

After Katie tells him that she is pregnant with their third child, he stops drinking and immediately falls into a deep depression that ends with his death from alcoholism-induced pneumonia.

He shows more emotion when his father dies than Francie, who reacts to the loss by becoming even more determined to get an education and rise above her mother's limited vision.

Eva "Evy" Rommely Flittman is Katie's youngest sister and Francie's other aunt, playing a role more minor than Sissy's.

Mary cannot read or write English, but she encourages Katie to ensure that her children learn the language, and also to begin saving money so she can buy land someday.

Although the book addresses many different issues—poverty, alcoholism, lying, etc.—its main theme is the need for tenacity: the determination to rise above difficult circumstances.

Other issues the book addresses include: On October 7, 1947 Studio One on CBS aired A Tree Grows in Brooklyn starring Rosemary Rice as Francie.