My favourite collection i've read so far, most of the stories are not as well known with the exception of The Final Problem introducing Professor Moriarty, this collection also introduces Holmes brother Mycroft.
These stories show Holmes in a different light to previous works, we have the story that introduced sleuthing as career to Holmes, we have cases turn out not as planned and a human side to the great detective, these character developments make this an interesting part of the Holmes stories.