Misir Ali Omnibus 1 is the place to begin Humayun Ahmed’s famous parapsychology professor series. The first omnibus collects the early novels in which Misir Ali takes shape as a character, the quiet pipe smoking university teacher who tries to find rational explanations for things that often refuse to be explained.
If you have never read Misir Ali, this is the natural starting point. The novels are short and each can be read in one sitting.