When he was not publishing case studies or studying complex psychological problems, Oliver Sacks, author of “Oaxaca Journal,” spent time studying ferns in Mexico.

As part of the New Haven Free Public Library’s lunch hour book discussion series Thursday, “Books Sandwiched In,” Joseph LaPalombara, professor of political science, led a discussion on Sacks’ recently published book.

A renowned neurologist, Oliver Sacks’ research was the basis for the book and film “Awakenings.” He has also published collections of case studies concerning Tourette’s Syndrome, Parkinson’s disease, and phantom limb syndrome. But in addition to his neurological credentials, Sacks is a member of the American Fern Society. “Oaxaca Journal” is the collection of his field notes from a trip to Oaxaca, where he joined a group of “fern enthusiasts” in their search for various types of ferns and mosses in the region.

During his presentation at the United Church on the Green, LaPalombara said he was fascinated with Sacks’ comprehensive discussion of both the natural history of the region and the impact of the Mexican government on the culture of Oaxaca. He spoke about the many times he had to stop and think about something the author was saying in the book.

“The revolution of Mexico was not long after the [American] revolution, but the highly authoritarian systems in Mexico remain corrupt up until today,” LaPalombara said.

LaPalombara said several times that the book was worth reading, but did note some of its negative aspects.

“I would have liked a more in-depth analysis,” LePalombara said. He also criticized the highly technical language the author used when describing the ferns.

But overall, LaPalombara spoke positively of “Oaxaca Journal” and said it had sparked his enthusiasm for ferns and mosses.

“We have mosses and ferns in our land in Maine,” he said. “I am going to go try and figure out what they are now.”

Approximately 30 people attended the event, and many of them were enthusiastic about the comments LaPalombara made about the book.

“I am going to go buy the book,” said Betty Mettler, a New Haven resident.

Jose Rivera, also a local resident, said he enjoyed the anthropological discussion about the Oaxaca area.

“I am from Puerto Rico, and sometimes I don’t know how people in other countries such as Mexico live,” he said. “It was nice to find out about the cultural differences in Mexico.”

Arlette Miller, a former member of the committee that chose which books to discuss at these sessions, said “Books Sandwiched In” has grown immensely since it first began in 1972.

“The series was originally started by Mabel Devane and Martha Shattuck, who modeled it after a similar program at Rochester University,” Miller said.

But the audience for “Books Sandwiched In” grew so large that organizers had to move it to the United Church on the Green where, for four more weeks this fall, Yale professors and other academics will discuss selected books.

Next Thursday, Hofstra University professor Magnus Bernhardsson will speak on Bernard Lewis’ book, “What Went Wrong?: Western Impact and Middle Eastern Response.”