Reading leibniz is always a pleasure as well as quite a challage and on the more difficult subjects, such as this book, one would hope to find help in the rather extensive footnotes provided by this translator. Much to my disappointment the footnotes was never meant to clarify anything, save perhaps for the utter contempt the translator has for Leibniz. For the first two letters chosen, the footnotes exceeded the the text by far and none of it dealt with the subject beyond casting doubt over leibniz' explanations on how he came to perceive his calculus. Several footnotes were so hateful, that you wonder why J.M. Childs even bothered to translate the letters in the first place. He could well have written all that in a seperate book, leaving that garbage to the die hard leibniz haters in London and elsewhere.

The dislike of the translator and the extent of it, also leaves you wondering whether the more difficult to understand passages is even translated correctly. I would advice caution reading this book as the intent seems to be to establish that it was a secret Barrows-Newton correspondence (one not even provided evidence for) and not Leibniz' own work, that developed the differential calculus. For a more fair assessment of Leibniz' calculus, look up Bruce directors "Riemann for anti-dummies" and the work of the Worldwide LaRouche Youth Movement. These people with whom i am associated has some of the best presentations of the tradition of Leibniz, kepler, Cusa, Riemann, Gauss et. al.
-Enjoy