Despite, or because of, its inclusion of hundreds of interviews, much of Greg Lawrence's biography amounts to uncorroborated hearsay. Given the backbiting and jealous atmosphere of the theatre world, a more rigorous biographer would have carefully weighed and vetted the reliability of the sources. Lawrence apparently was not given access to Robbins' own papers and therefore the man himself is decidedly absent from these pages, as has been pointed out by reviews in The Wall Street Journal, The New Yorker, and elsewehere. It's gossipy and full of facts and opinions, but curiously empty.
Another customer reviewer here compares Lawrence's book with Christine Conrad's compendium of photographs and Robbins quotes (Jerome Robbins,That Broadway Man, That Ballet Man), to Lawrence's benefit. Seems to me you get a stronger sense of Robbins the man AND the artist from Conrad's book, even though it doesn't pretend to be a biography.
I've read that two other full-scale biographies are in the works whose authors have been allowed to see Robbins's archives; hopefully they will provide a deeper and more balanced view of the man. If anyone still cares.