Writer and children’s book author Robert Kimmel Smith, widely known for such popular middle grade novels as Chocolate Fever and The War with Grandpa, died on April 18 at his home in Manhattan of natural causes. His wife, Margery Nathanson, confirmed that he had suffered from Alzheimer’s disease since 2015. He was 89.

Smith was born July 31, 1930 in Brooklyn, N.Y. and grew up near Ebbetts Field, able to walk to games in the bleachers and cementing his lifelong love of baseball. An early reader, Smith told Something About the Author that he was so enamored of adventure tales of pirates and the Wild West that he saw authors as heroes. He began jotting down his own stories in grade school and continued that pursuit into high school, at which point he told his parents of his ambitions to become a writer. “They said, quote, ‘There’s no way you can ever make a living,’ ” Smith recalled to SATA.

Heeding his parents’ urging to have a career to fall back on, Smith enrolled at Brooklyn College to begin pre-med studies. But he quickly realized college wasn’t a good fit, and dropped out. Soon after, he was drafted into the U.S. Army. He was stationed in Germany where he told SATA “there was a very fine post library” he could use, and where he and some fellow soldiers wrote musical revues and formed a barbershop quartet.

Back in New York following his discharge from the Army in 1953, Smith met Claire Medney on a blind date. “She loved books and reading as much as I did,” he told SATA. After that first date, Smith and Medney both told their mothers they had met the person they were going to marry. The pair wed in 1954 and settled in Brooklyn, again near Ebbets Field. They would eventually welcome a daughter and a son.

Smith worked as a traveling salesman among other things during the mid 1950s before landing a position as a copywriter at advertising firm Doyle, Dane, Bernbach in 1957. “That’s where my education in writing really began,” he said in his SATA interview, noting that he benefited from the discipline of sticking to a deadline. Smith rose through the ranks in advertising, becoming a copy chief at Grey Advertising and then in 1967 forming his own firm, Smith & Toback, with partner Harvard Toback.

Throughout his ad agency years, Smith sold several pieces of short fiction to magazines under the pseudonym Peter Marks, all the while holding on to his dream or writing a novel. He has credited his wife Claire, who became a literary agent at Harold OberAssociates, with being his best editor and great supporter. On January 1, 1970, Smith embarked on a new career path and became a full-time writer. The first manuscript he completed was inspired by a humorous story he had been telling his then-seven-year-old daughter Heidi about a boy who loved chocolate more than anything else. The result was Chocolate Fever, which was published by Coward McCann and Geoghegan in 1972. The book has remained in print over the years and has sold more than two million copies.

With that first book under his belt, Smith was writing at full steam, publishing a trio of novels for adults with Simon & Schuster starring Sadie Shapiro, a wisecracking septuagenarian known for her knitting, as well as the more serious Jane’s House (Morrow, 1982) about a husband and family grieving the untimely death of their wife and mother. It was produced for television in 1994 in a movie starring James Woods and Anne Archer. Smith also wrote several plays and television scripts during this fruitful period.

By the early 1980s, Smith again focused on writing for children. The War with Grandpa (Delacorte, 1984) tells the tale of Peter, a boy who is not happy about relinquishing his bedroom when his widowed grandfather comes to live with the family, so he declares war. The novel won 11 IRA-CBC Children’s Choice state reading awards and has been adapted as a feature film starring Robert De Niro as Grandpa, slated for release later this year. Delacorte plans to simultaneously publish a movie tie-in edition.

Claire Smith died of lung cancer in 1998. In 2000, Robert Smith married Margery Nathanson, former director of design services for the New York City Department of Transportation, gallerist and collector of Latin American folk art. Their family recalled in an obituary note that Smith serenaded Nathanson at their wedding ceremony and continued to do so during the two decades they shared together living in Manhattan.