When fortune carries me to Ireland, nightfall typically finds me looking for the pub with the best session.

Sessions are perhaps one of Ireland's greatest gifts to the world. In most pubs, you'll find a table or booth somewhere marked "reserved for musicians." And in the evenings they come, showing up with their instruments to play the night away in good company, over a good many pints of Guinness and the din of clinking glasses and barroom conversations.

It seemed a good idea to help create such a thing on this side of the ocean, specifically in my own hometown where I could enjoy such evenings on a more regular basis. With the help of several local musicians, we seem to have done fairly well with our sessions here in central Pennsylvania ... but, according to Barry Foy, we're doing them wrong.

Foy, a writer and musician from Seattle, expounds at great length on the customs and rituals of the true Irish session in his book, Field Guide to the Irish Music Session. The slim volume is a quick read and is entertaining to the last drop. He's clever, witty and brimming with knowledge on his subject.

Musicians may want to avoid taking Foy too seriously, however, lest his abundance of rules squeeze the joy out of the music. He revels in the spontaneity of sessions and yet advocates a strict set of thou-shalts and thou-shalt-nots in their execution. I choose to ignore the inherent contradiction and assume his admonitions are largely tongue-in-cheek in nature. (Can he really be suggesting that musicians be spontaneous in precisely this way?)

He is, for instance, quite dogmatic on the subject of instruments allowed at a session. Fiddlers and pennywhistlers, be welcome! Guitarists ... well, maybe just one, if he's good. But anyone brazen enough to bring a recorder, hammered dulcimer or viola to the room should be snubbed and banished. (Oddly, Foy likes the bouzouki, a decidedly non-Irish instrument from Greece, but frowns on any new incursions into the circle. Such an attitude, if taken seriously, would encourage stagnation and would eventually delegate Irish sessions into little more than museum pieces.)

Where he gets it right is in the communal tone of sessions. They're not meant to be recitals, spotlight performances or anything else that strokes the ego of the individual musicians. They're fun, they're interactive, they're cooperative, they're encouraging. As Foy notes, "To think of sessions as strictly musical events is to harbor a misunderstanding. They are also social events. The musician who pours his whole heart into the playing but ignores the social give-and-take is not only a bore to play with, he also doesn't do the music any favors."

He's also right in acknowledging that a good session involves a steady flow of beer for the musicians. Some points go without saying.

A few philosophical differences aside, Foy has written a deucedly clever, revealing book on the subject of Irish sessions. A few extras, like his do-it-yourself tune titles and his glossary of important terms, are gems not to be missed. And what session musicians won't read the text and see a little bit of their fellow players -- and, ultimately, a bit of themselves -- in Foy's descriptions?

If you play Irish music, if you enjoy listening to Irish music, if you enjoy a dry wit with a lot of character, Field Guide to the Irish Music Session is a winner.