After 18 years of pizza study breaks and dessert socials, Donald H. and Cathleen K. Pfister will step down from their positions as Kirkland House masters in June.

In a letter distributed to House Residents and tutors last Thursday, the Pfisters announced their plans to resign. After 18 years, the Pfisters said, they have gotten restless and feel it is time to move on. Appointed in 1982, they are currently the longest-serving Masters at the College.

"One wants to have the time to do other things," Donald Pfister said.

Next semester, the Pfisters will move to a house in Arlington. Cathleen Pfister said she hopes to find some time to relax, while her husband hopes to dedicate more time to his work at the Harvard Herbarium of Cryptogamic Botany and research with graduate students.

Donald Pfister is Gray professor of Systematic Botany and curator of the Farlow Reference Library and Herbarium. He has taught at Harvard since 1974.

Cathleen Pfister, an admirer of art and art history, works at the reference desk in the Botany Libraries. Both will retain their current positions at Harvard.

Tutors and students in Kirkland House have expressed appreciation for the Pfisters' dedication to the House.

"The main thing I can say of the Pfisters would be their immense pride in Kirkland House," wrote Laura T. Lee '00 in an e-mail message.