CALAIS, Maine — When Marilyn Sotirelis retires at the end of June — after 34 years as the Calais city librarian — she plans on doing two things: heading off to volunteer at the Calais Elementary School library, and sitting down to read a good book.

As she reminisced this week on her career, Sotirelis said, “It was never, ever about the books. It was about the people.”

She said that since announcing her retirement a month ago, she has been privately saying goodbye to her patrons, a task she admits has been difficult. “We are sharing our memories, one on one.”

Besides the patrons, Sotirelis said she also will miss the view from the castlelike library that overlooks the St. Croix River. “It has been such a constant,” she said.

Diane Barnes, Calais City Manager, said the city is seeking Sotirelis’ replacement, but added, “We can replace the position but never the individual. The continuity of service, and friendly face for so many years is not going to be easily replaced.”

Sotirelis has been head librarian at Calais since 1984 and during that time has watched the library transform through technology. She said an addition was built in 1985 and a major renovation in 2002 brought the library not just into the 21st century, but reinforced the original building for a few more decades.

Inside, a bank of computers is now heavily used, 40 percent of her patrons are from New Brunswick, the collection has been completely logged online and an art gallery has been added. The Calais Free Library also continues to be one of the heaviest users in northeastern Maine of the interlibrary loan program. Sotirelis also has written and obtained several grants, including one that installed air conditioning in the children’s room, and has put great emphasis on the genealogy section of the library.

“In some ways, you wouldn’t recognize the library I started with compared to today. But we are offering the same services originally offered in 1892, just in a different format,” she said. “We now have audio, video, DVDs, and the ability to download to an e-reader.”

Sotirelis started her career in libraries as a pro-tem librarian at the Special Services Library, U.S. Army Hospital Library in Heidelberg, Germany. Although Sotirelis earned her bachelor’s degree in education at the University of Maine and worked as a teacher in both the Perry and Pembroke elementary schools, her heart had decided that the world she really wanted was the one she had discovered in the that small library in Germany.

She was hired in 1979 as the part-time librarian at the Calais Elementary School, when the library was simply a room full of books. Sotirelis catalogued and shelved every book; then library volunteers were trained to help with checking out books for the children in all the classrooms. She jumped at the opportunity to work at the Calais Free Library shortly afterward and was hired as head librarian in 1984.

“I felt more joy on that day I was hired than nearly any other in my life,” she said. “I have treasured this work.”

In her 29 years as head librarian, Sotirelis is most proud of two accomplishments: handling each of the 40,000 library volumes at least three times as the collection was placed online and building the interlibrary loan program, which users can access from home. “We are truly a library without walls,” she said.

“I think people take pride in our library, as we do them,” she said. “Our patrons are our top priority every day. We don’t just say that. We live that.”

She said she has been honored to work with her board of trustees, the Friends of the Calais Library and the three other library staffers. “It is such a small staff that we get to know and love each other,’’ she said.

To prepare for this life change, Sotirelis said she recently read a book about how to retire. “It said you should have a plan. I don’t, but it doesn’t bother me.”

After summer vacation, however, Sotirelis said she will volunteer at the Calais Elementary Library.

“I see it as a circle. One lovely circle.”