BM Category Theory 10: Monad & Monoid

10.1 Monad
Analogy : 

Function : compose “.“, Id

Monad: compose “>>=“, return

Imperative (with side effects eg. state, I/O, exception ) to Pure function by hiding or embellishment in Pure function but return “embellished” result.

10. 2 Monoid

Monoid in category of endo functors = Monad

Ref Book : 

What is the significance of monoids in category theory? by Bartosz Milewski