Blackout is funny, tense, wacky, zany and extremely entertaining. The one thing it isn't is long enough.

OK, I understand that actually it was too long, forcing Willis to divide the tale between two books, Blackout and All Clear (to be published this fall), but even at 528 pages, I wasn't ready to stop reading.

As in many of Willis's previous books, the story begins at England's Balliol College, Oxford University, the ubiquitous Mr. Dunworthy presiding. The typically hinky Net (time travel machine) is once again on the fritz, and missions are going wildly astray on both ends of time. Although frustrating on this end, where trips are sometimes delayed by weeks, it becomes far more serious in the 1940s, where bombs are dropping on London and the Net refuses to open.

Several stranded historians scramble to find alternate routes home as they begin to overstay their assignments, but rescue fails to arrive.

The narrative follows three historians in 1940: Mike, unhappily participating in the rescue of soldiers from Dunkirk in 1940 (when he should be at Pearl Harbor); Polly, posing as a shop girl in Townsend Brother's department store, and Eileen, researching the Children's Evacuation in Warwickshire, in the London countryside. Running concurrently (but not yet tied in) is Mary, who'd rather be at VJ Day, but is stuck waiting for the Germans to begin dropping V1s ( a type of bomb) on London in 1944.

Any Willis novel is so extraordinarily complicated as to defy easy summary, and any detail revealed in advance is one too many. Suffice to say, I read Blackout in less than one week and will read it again at least once before relief comes with All Clear.