The Light Heart, the fourth installment in Elswyth Thane's Williamsburg series, covers the years 1902 to 1917.The reader enjoys these stories of the Days and the Spragues families in this saga series of novels, in successive generations, as one might the Whitecaks of Jalna series. The last novel bridged the Atlantic, with two inter-marriages, so now this next one again is set partly in Williamsburg, partly in New York, partly in London (and briefly in central Europe). This time World War I provides the background, while England of two coronations - Edward VII and George V - spans the story. Once again it is a story of the Spragues and the Days, and now their English connections; Phoebe, cousin (and niece) of Cousin Sue is heading into a situation of being "lost for love". Cousin Sue finds a way to rescue her from a childlike devotion to "poor Cousin Miles" - and sends her abroad, only to the love for Oliver, despite his engagement to the jealous Maia. So Phoebe goes back to marry her Miles and finds she can't go through with it. A war takes her back to Europe, with intention to rescue Rosalind from her German Prince - and again she finds in Oliver the same overwhelming love. Lovely Phoebe Sprague, of Williamsburg, Virginia, though still engaged, falls in love with Captain Oliver Campion. But in 1902, a betrothal was almost as binding as marriage? Is it too late?