Told that his project of writing an autobiography is premature, Humphrey (one of those Church Mice who have cavorted so hilariously through eight previous books) keeps a yearlong diary whose style bears some resemblance to that of the terse but pithy Pepys. The diary device gives Oakley the opportunity to present a series of brief episodes, such as Humphrey imagining that Princess ""D"" has sent him a valentine, Sampson (the benignly golden cat) besotted with a Siamese who terrorizes his mouse friends, and 57 mice independently but simultaneously dressing up as Santa, to the surprise of their young. Each succinct incident is so well stated that it leaves plenty of room for extension in the reader's imagination. As always, both Oakley's full-page illustrations and the many vignettes are full of entrancing details of the antics of the animals, and of the English village where they take place. Fans should be delighted by this latest comic excursion of the irrepressible mice from the vestry; they may hardly notice that the wry humor has a lot to say about humans as well.