It is clear that Bennington "gets" Derrida in this work. Bennington is easily one of the (maybe) 2 or 3 persons alive that are even nearly qualified to "finish Derrida's sentence." Everything I read of his is almost as if Derrida, himself, were writing.
Though an excellent look at exactly what Derrida is up to in his early days from Grammatology to Glas, this is not for the beginner. "Deconstruction in a Nutshell" by John Caputo and "How to Read Derrida" by Penelope Deutscher are better for introductory purposes.
This work was indispensable for me, as I was introduced to Derrida through his later works and had very little idea how his whole project began in the 60s, 70s, and 80s.
If you are fairly experienced in theory, I would recommend laboring through this work, then re-reading it a couple years later after further work with Derrida, Heidegger, etc. It will clear up a lot of question marks while opening up new, more exciting ones.