Who says it doesn't pay to send a letter to the president of the United States?

It did for eight people from around the country who told President Barack Obama how his policies helped them overcome personal hardship. The White House invited all eight to sit with first lady Michelle Obama when Obama delivers the State of the Union address Tuesday night.

Obama also met in the Oval Office on Tuesday with four of the letter writers.

The eight are among 22 people the White House invited to attend the speech, including Alan Gross, the Maryland man recently released from five years of imprisonment in Cuba, astronaut Scott Kelly and CVS Health CEO Larry Merlo. Gross will attend with his wife, Judy.

It has become tradition for presidents to invite people whose stories of tragedy or triumph highlight an issue or public policy.

President Ronald Reagan was the first to do so in 1982 and acknowledge the guests during the speech. Every president since has carried on the tradition, and lawmakers increasingly are bringing guests, too. Among their guests are several Cuban activists, former New Orleans Saints player Steve Gleason, who is afflicted with Lou Gehrig's disease, and celebrity chef Tom Colicchio.

Gross, a former federal subcontractor, was freed from Cuba last month as part of Obama's historic announcement that the United States would restore diplomatic relations with Cuba.

Kelly, of Houston, is preparing to blast off in March on a yearlong space mission, the longest of any U.S. astronaut. His twin, retired astronaut Mark Kelly, is married to former Rep. Gabrielle Giffords, D-Ariz. Giffords was gravely wounded during a shooting at a political event she held in Tucson four years ago. Scientists will compare medical data from the Kelly brothers to study how the human body responds to longer durations in space.á

CVS Health pulled cigarettes, cigars and other tobacco products from its store shelves last year, a move that was applauded by Obama, a former smoker. The decision earned Merlo, the drugstore chain's top executive, a seat in the first lady's box for the speech.

The letter-writers, as identified by the White House, are:

-- Malik Bryant, of Chicago. The 13-year-old wrote a letter to Santa over the holidays asking for safety. Instead of forwarding the letter to the North Pole, a nonprofit organization redirected it to the White House. Obama wrote back to say that security was a priority for him, too.

-- Rebekah Erler, of Minneapolis. The wife and mother of two young boys wrote to Obama about how her family suffered after her husband's construction business folded. Both parents are working again and recently bought their first home. Obama spent a day with Erler in Minnesota last year.

-- Victor Fugate, of Kansas City. Fugate told Obama how he went from being an unemployed new father to getting his degree and helping low-income patients obtain medical care. Fugate says he and his wife are benefiting from an Obama program that caps monthly student loan payments. Obama met Fugate in Kansas City last year.

-- Retired Army Staff Sgt. Jason Gibson, of Westerville, Ohio. Gibson wrote to thank the president for visiting him as he recovered from injuries, including the loss of both legs. Gibson surfs, skis, has completed marathons on a hand cycle and earned a pilot's license. He became a father in November.

-- Katrice Mubiru, of Woodland Heights, California. Mubiru, a career-technical education teacher in Los Angeles, encouraged Obama in a letter to support K-12 adult and career technical education. She introduced Obama last year when he visited Los Angeles Trade-Technical College to promote technical skills programs.

-- Astrid Muhammad, of Charlotte, North Carolina. Muhammad, a wife and mother of two, wrote to thank Obama for signing the Affordable Care Act. She obtained coverage under the law last year and had surgery to remove a potentially fatal brain tumor that was diagnosed when she had no health insurance.

-- Carolyn Reed, of Denver. Reed described for Obama how she expanded her submarine sandwich shop business with a government loan. Obama dined last year with Reed and other Coloradans who wrote to him. Reed also told the president she was raising her hourly employees' wages to $10.10.

--Ana Zamora, of Dallas. A student at Northwood University, Zamora was brought to the United States illegally as a child and has benefited under Obama's program to defer deportations for eligible immigrants. Zamora wrote Obama about her experience and says her parents will also be eligible for protection under his recent executive actions on immigration.

The remaining guests are:

-- Chelsey Davis, of Knoxville, Tennessee. Davis is scheduled to graduate in May from Pellissippi State Community College. She met Obama when he visited her school this month to announce a plan to pay for two years of community college for students who keep up their grades.

-- LeDaya Epps, of Compton, California. The mother of three completed a union apprenticeship in construction and is on the crew building the Crenshaw/LAX light rail line. Obama has promoted apprenticeships as a way for people to get training for skilled jobs.

-- Nicole Hernandez Hammer, of southeast Florida. The sea-level researcher studies how cities and other areas most vulnerable to the effects of climate change also have large Hispanic populations. She works to raise Latinos' awareness of climate change. Obama has taken steps to address climate change.

-- Anthony Mendez, of New York City. The University of Hartford freshman once had to rise at 4:30 a.m. to get to school after his family was evicted and living in a homeless shelter hours away. Mendez was among students who met Mrs. Obama last year. She spearheads an initiative encouraging students to pursue education after high school.

-- Kathy Pham, of Washington, D.C. Pham is a government computer scientist who works to improve health information technology, expand access to benefits for veterans and improve how government provides services.

--Capt. Phillip C. Tingirides, of Irvine, California. A husband and father of six, the veteran Los Angeles police officer heads the Community Safety Partnership program in the neighborhood of Watts, once scarred by race riots and subsequent gang violence. Police engage with residents under the program.

-- Catherine Pugh, of Baltimore. Pugh is majority leader of the Maryland Senate and helped pass legislation increasing the state minimum wage to $10.10. She has also introduced legislation to provide workers with earned paid sick leave. Both are issues Obama is pushing at the federal level.

-- Dr. Pranav Shetty, of Washington, D.C. Shetty is the global emergency health coordinator for International Medical Corps, a partner in the U.S.-backed effort to control the Ebola outbreak in West Africa. Shetty went to Liberia in August, returned to the U.S. last month and heads back to West Africa this week.

-- Prophet Walker, of Carson, California. While serving time for robbery, Walker started a prison program to help fellow inmates earn a two-year degree. After prison, he became a construction engineer and has worked to improve relations among law enforcement, community activists, parents and the children of local housing projects.

--Tiairris Woodward, of Warren, Michigan. Woodward started a second job working on Chrysler's assembly line in 2010 to help support herself and three children, including one with special needs. She eventually began working only for Chrysler and after a year had saved enough money to buy a car and rent a new apartment. The company's tuition assistance program is aiding her pursuit of a bachelor's degree in business management. The White House says her story is possible due to the comeback of Detroit and the U.S. auto industry.