A little while ago, I reviewed A Crack in the Line, by Michael Lawrence. It wasn't a timeslip book, but it was similar in mood. That book tells of two teenagers (Alaric and Naia) who are each other in alternate realities. The line between their realities blurs, with concomitant disorientation (a feature of many timeslip stories), and in the end, they take each other's place.
The sequel, Small Eternities (2004 UK, 2005 US, Greenwillow, YA, 322 pages) picks up where the first book left off, with Alaric and Naia trying to feel comfortable in each other's life, and then heads off into time travel. The split in reality, it turns out, was caused by something that happened back in the 1940s, and Alaric was there. What is more, he was the unwitting cause of a tragedy that sent his long ago relation, Aldous Underwood, travelling into alternate life paths of his own...
The three points of view--Naia, Alaric, and Aldous--bring to the reader three very different characters. All three, however, are bound by a common thread of uncertainty and loss, and I found the result both fascinating and moving. Somehow Lawrence managed to tell this rather complicated and inexplicable story of characters hopping in and out of realities in a way that allowed me to suspend the peevish disbelief that sometimes happens when I'm being told a story with unreliable events/narrators, in which confusion is a large part of the plot. I think I was helped by the steady stream of detail about people and places that Lawrence pours into his story--he might not give easy answers, but he does create a very vivid and tangible world, providing firm footing for the reader's mind (as it were).
I enjoyed it more than the first book--there seemed more reason for things, even though I continue to have unanswered questions. The only thing I hold against Lawrence is the end. Not fair, especially to mothers of boys.
Timeslip wise: Falls into the "not explained clearly" category. Time travel is important as a plot device for the story of the characters in the present, more than as a way of allowing the characters to experience the past. The world of the 1940s is part of the book, but in a minor way, and primarily is seen from the point of view of young Aldous, who was living it, rather than Alaric and Naia, travelling back to it.
(I can't say I fancy the cover much. It reminds me all to vividly of what is happening in my son's school-made plastic soda bottle terrarium, inhabited at the moment by one lonely fish for whom I feel very sorry)