# Book of Pullbacks and Pushouts

what books can I consult for properties of pullback and pushouts in algebraic topology?

I need to understand the theory of homotopy in algebraic topology and I started to study pullbacks and push outs, some help please.

-
I would start with math.uchicago.edu/~may/CONCISE/ConciseRevised.pdf . I would also look into Model categories. –  Baby Dragon Feb 25 '14 at 6:06
thank you very much. –  Knight Feb 25 '14 at 6:22
You could look at my book "Topology and Groupoids" pages.bangor.ac.uk/~mas010/topgpds.html, which goes from adjunction spaces to pushouts, and does a lot on groupoids in $1$-dimensional homotopy theory. –  Ronnie Brown Feb 25 '14 at 12:08
Any book on homological algebra will do, say Rotman's –  Alexander Grothendieck Feb 26 '14 at 0:04