An enjoyable adventure, notable for good location shots of London, not the obvious tourist's traps, and the highlands of Scotland. Having identifiable locations increases the local tourist trade, many people want to visit the"scene of the crime".
Does it matter that the film didn't follow the book too carefully. Was it entertainment in its own right, or do we want to follow the scenes and dialogue, like some old theatre and concert goers with their carefully annotated "libretti". No,the movie industry stands on its own feet, and of course it uses literature. Didn't the original author not take classical themes, innocent man accused of criminal activity, trustworthy persons in power turn out to be the baddies, boy meets girl, loses girl, refinds girl. There really cannot be total originallity in any modern work of creativity, all is based on what has gone before.
Thirty nine steps, a ripping good yarn, to be enjoyed in the spirit in which it was offered.