Category Theory for Scientists
http://math.mit.edu/~dspivak/teaching/sp13/
Also, here's a link to Spivak's [unpblished?] book http://math.mit.edu/~dspivak/CT4S.pdf
Also, here's a link to Spivak's [unpblished?] book http://math.mit.edu/~dspivak/CT4S.pdf