BOSTON PUBLIC FOX, 8-9 PM DEBUTS OCT. 23

With his name on three prime-time series this season, it's pretty clear what David E. Kelley did on his summer vacation. The question is, has Boston Public -- Kelley's quirky (natch) new Fox drama about overworked teachers in a struggling Beantown high school -- been a full-time concern for the prolific auteur or a mere extracurricular activity, a la last season's disastrous distaff private-dick series, Snoops?

''The network has no concerns about that at all,'' avows Fox Entertainment president Gail Berman. She adds that Kelley has thus far personally scripted the first six episodes of Public, in addition to fulfilling his duties on Ally McBeal and ABC's The Practice. In fact, boasts Berman, ''we have more episodes of Boston Public on hand than we do of any other new show.''

Kelley may be king of this blackboard jungle for now, but he is delegating day-to-day show-running duties to executive producer Jonathan Pontell, whose collaboration with the Ally creator dates back to the pair's L.A. Law days. Pontell admits that Public's grittier setting makes realizing the master's vision a tad easier than on its 9 p.m. lead-out. ''Ally was more [a mix]between reality and fantasy. The tone of that show was so much more in David's head, so it was hard to always tap into that,'' he says. ''This is reality.''

Um, not so fast. Although there are no dancing babies or habit-clad serial killers (at least not yet), Kelley has imbued Public's ensemble with a gymnasium full of eccentricities. Among the instructors at the fictional Winslow High are a high-strung staffer, Marla Hendricks (Loretta Devine), on the verge of a nervous breakdown thanks to the delinquents she oversees in the school's ''dungeon''; a much-abused English teacher (The Single Guy's Joey Slotnick); and a dotty old-timer, Harvey Lipschultz (Fyvush Finkel), who attributes Winslow's ills to school integration (in the form of its African-American ''desegs'') and who forces his recalcitrant history students to sing the national anthem. Rounding out the faculty freak show is geology instructor Harry Senate (Nicky Katt), a cross between Mr. Chips and Travis Bickle, whose idiosyncrasies range from the unsavory (he's carrying on an affair with one particularly precocious student body) to the downright inflammatory (the antiviolence demonstration he enacts for one class of sweathogs has to be seen to be believed).

Leading the loopy troops is Chi McBride (previously the eponymous footman of UPN's infamous Civil War sitcom The Secret Diary of Desmond Pfeiffer) as Steven Harper, the school's harried principal, who defines Winslow's mission more as educational triage than life preparation. ''He's like the guy on the old Ed Sullivan Show spinning the plates on the sticks,'' he says. ''There's no time to say, 'Oh, I gotta get this one spinning real good,' because the rest of them are going to be on the ground in pieces.'' As a result, says McBride, ''he leads by example, and the fact that he colors outside the lines may be what inspires the teachers to do the same thing.''