The 1996 Doctor Who movie divided opinion amongst fans but is generally considered to be a critical and commercial failure. The film itself is a bit of a mess; on the plus side it gave Sylvester McCoy's Seventh Doctor a decent exit and provided, in Paul McGann, a worthy successor. On the downside, Eric Roberts hams it up terribly as The Master whilst the middle section of the fim is garbled, poorly thought out, and frankly boring.
Anyway, the book of any film obviously enables the reader to envisage events in their own minds, particularly if they haven't seen the film in question. Russell does a decent job of making the story come to life and his characterisations are generally more rounded and interesting than they are in the film.