For non-mathematicians (although some post-secondary maths is probably required), I'd also recommend Spivak's "Category Theory for the Sciences" (MIT Press, 201

For non-mathematicians (although some post-secondary maths is probably required), I'd also recommend Spivak's "Category Theory for the Sciences" (MIT Press, 2014) and Milewski's "Category Theory for Programmers" (available online at https://bartoszmilewski.com/2014/10/28/category-theory-for-programmers-the-preface/ https://bartoszmilewski.com/2014/10/28/category-theory-for-p...). I liked it enough to buy the hardcover.