I have a decent background in differential geometry. I have read John Lee's [introduction to smooth manifolds](http://rads.stackoverflow.com/amzn/click/0387954481) and doCarmo's Riemannian Geometry. I was trying to read Misha Gromov's [Metric structures for Riemannian and non Riemannian spaces](http://en.wikipedia.org/wiki/Metric_Structures_for_Riemannian_and_Non-Riemannian_Spaces) but am finding it extremely difficult to follow. Any suggestions for books/papers as prerequisites ?



Background to understand Gromov's green book
Slightly more advanced books on Riemannian geometry can help, in particular Petersen, and Gallot-Hulin-Lafontaine. Gromov draws a lot of his examples from Riemannian geometry !


Reading Burago-Burago-Ivanov "Introduction to metric geometry" is a also a good idea. It will give the necessary understanding of intrinsic metric spaces. 


With this a good part of the book should be understandable. 


