In Year of the Griffin, Diana Wynne Jones returns to a world she's written about twice before - in the children's novel The Dark Lord of Derkholm, and in the adult(?) book The Tough Guide to Fantasyland. It's a pity, too, because the books have been declining in quality as she goes. The Tough Guide was a reasonably funny book for readers of fantasy and RPGers, Dark Lord was a rather standard, empty romp, and now - Year of the Griffin. Which, unfortunately, has the characteristic Jones tone, but lacks the wit, the intelligence, and especially the cohesive plot of her best books.
The eponymous griffin is Elda, the daughter of the human magician Derk, and the year portion of the title refers to her freshman year at the magical university. (Please, no comparisons to Hogwarts or to the Unseen University - it isn't in the same league as either.) The university is seriously strapped for cash, and the members of Elda's class all have secrets - and most of them are being hunted for one reason or another.
The freshmen become a group, and together repel assassins, parents, and problems in ways that should be thoroughly hilarious, but somehow aren't. The feel of Jones' former works is present but the joy is not. Much of the problem appears to be that the author is too fond of her characters; the gigantic but gentle Elda and her cohort occupy a lot of the space that should be plot. The book feels stretched and very light, like a two-page essay made to look like an 8 page one.
It isn't necessary to begin this series at the beginning; if for some reason you want to, you can begin with Year of the Griffin. But if you've never read Jones before, start with her children's classics - Archer's Goon, The Ogre Downstairs - or her best adult novel, Deep Secret. It pains me to say this, because I love Jones' writing, but - unless you're a diehard fan, give Year of the Griffin a miss.