Three wonderful essays entitled “The Inevitability of Evolution”, which go on to explain that if you think evolution by natural selection is impossible then you simply don’t understand it.
They are rather short so please read them all!
Part 1 explains that treating the entire sequence (from bacteria to human) as one big, impossible probability is to miss the point, and is like saying “the chances of English history happening the way it did is impossible”.
Part 2 explains that staring at a petri dish of bacteria and complaining that it has not yet turned into a platypus is forgetting the fact that there are billions of bacteria in the world and they are all reproducing and evolving together over millions of years.
Part 3 explains the nature of biology, that even if the chances of a mutation occurring were slim (they are not), they only need to happen once. After that, all the creature’s descendants are born with those mutations as a starting point, and so each step of the way has the same chance as the previous (which, given the sheer volume of creatures and the length of time involved, is nearly certain).
The ‘gigantic casino’ analogy is one of the best ways of explaining this that I have ever read!