“I feel like I’m starting all over again,” Mr. Frommer said. “I’m working hard to bring them back to what they were.”

Mr. Frommer, often considered the father of the travel-guide business, wrote and published his first guide, “The G.I.’s Guide to Traveling in Europe,” when he was a young Army corporal living in Berlin.

That guide, turned into a book called “Europe on $5 a Day,” became a huge success. Several years later, after a brief career practicing law, Mr. Frommer began publishing more travel books, building a business to be a leader in the industry. For many years, Mr. Frommer said, the Frommer’s books made up close to 25 percent of all the travel guides sold in the United States.

He has not had direct control over the Frommer’s guides for decades. In 1977, Frommer’s was sold to Simon & Schuster and later acquired by John Wiley & Sons. (Mr. Frommer remained involved as a consultant.) Last year, Google paid about $23 million for the brand, saying that it would incorporate the Frommer’s content from its books, mobile apps and Web site into local reviews. This year, it sold the brand back to Mr. Frommer for an undisclosed price. By the end of 2014, Mr. Frommer expects to release as many as 80 books. Mr. Frommer and his daughter, Pauline, will be co-presidents of the company. A new series, called EasyGuides, are an answer to the increasingly lengthy travel guides on the market that Mr. Frommer said were too long to be practical.