Hi, What started as a simple exercise of writing an Airbrake integration for Spock, has turned into a day of reading about errors, Control.Exception, MonadThrow, MonadCatch, sync, asynchronous, etc. Even after all that reading I haven't been able to find answers to the following -- * What exactly is done by the "error" function? How does one "trap" those errors and react to it? Can "catch" trap those errors? What is "e" in the case of errors raised by "error"? * How is "error" different from "throw" and "throwIO" (in the Control.Exception package, I believe) * What does MonadThrow and MonadCatch bring to the table? My understanding is that they are bringing a unified API to representing short-circuitable computations based on the inherently short-circuitable value of the host monad. Eg throwM in Maybe just results in a Nothing. throwM in List results in [] Therefore, in most of the cases throwM is not really using the error machinery built into the Haskell language (what said machinery is, is the very first question that I still don't completely understand) All of this might be obvious, and I might have just reached a mind-block after hours of reading. Help would be really appreciated :) -- Saurabh.