By the Pricking of my Thumbs is hardly one of Christie's better novels. That's not to say its completely boring or a waste of time. Its quite interesting actually and there are parts which will keep your eyes glued firmly to the page. However, though the premise of this novel is pretty good in an eerie sort of way, it suffers from a mediocre plot structure, too many confusing and meandering sub-plots and clues which don't quite make much sense until they are explained in the end (something which is a strict no-no as far as whodunits are concerned). The novel significantly deviates from the conventional detective story format that Agatha Christie herself perfected. However, a major redeeming factor in this novel are its two likable and lively protagonists, Tommy and Tuppence Beresford.
Basically, I have just listed down the reasons why the film adaptation is better than the book (quite a rarity as far as film adaptations go!) The film, in contrast to the novel is somewhat more linear and structured in its story-telling. The inclusion of new, varied and interesting characters adds on tremendously to the background. A useless and confusing subplot from the novel is erased and as such there is greater focus on the central macabre plot. However, one aspect of the film which pales in comparison to the novel are the portrayal of the two protagonists Tommy and Tuppence. The actors may have played their parts to perfection and look about the same age the characters must have been in the book, but frankly, I always viewed Tommy and Tuppence as being a bit more youthful and fun in the book, regardless of their chronological age. Instead, in the film, Tommy is portrayed as tough authority figure and cold and distant husband, while Tuppence is the neglected wife who drinks away her sorrows. Furthermore, both characters are largely overshadowed by Miss Marple (who did not appear in the novel). However, one understands as since this film is no more than an episode in the 'Marple' TV series and that Tommy and Tuppence are not really that big brand names to have their independent adaptations, one doesn't mind so much.
