In this volume, Wirszubski delves into the problem by examining Pico's sources, particularly the translations made for him by the convert Flavius Mithridates. Wirszubski compares those translations to the original texts Flavius must have used, and shows that the translations were often highly eccentric. By reading very closely into these sources, then, we are able to determine something of what Pico must have thought Kabbalah was like in its original Jewish form.
From this point, we can to some degree extrapolate Pico's Christian synthesis, the starting-point of all later Christian Kabbalah (although see also Reuchlin's works).
Wirszubski's work is extremely difficult, and not for the casual reader. A working knowledge of Latin is essential, and a smattering of Hebrew would help. Furthermore, the analysis presumes a fascination with the minutiae of source-criticism and considerable expertise in the intellectual history of the Florentine Renaissance. The analysis is meticulous, the notes extensive. Wirszubski also demonstrates --- although this is hardly his intention --- why nobody does source criticism on Christian Kabbalists: you have to know everything!
Overall, this is an essential work for the specialist, and one that should be in every serious library of early modern occult sciences. I suspect that the lay reader will find it incomprehensible and boring, and it is inappropriate as an introduction to the subject for any reader. If you have already read Scholem and Idel on Kabbalah, and Yates, Walker, et al. on early modern occultism, however, this is sort of the next level. One could wish there were more studies like this, but there are very few people who could write them. Wirszubski's study is a unique masterpiece.
Nonetheless we are left with the sole account of the first important mixture of two very important movements: Christian mysticism yearning for reformation and the Kabbalah which had found its own reformation behind the backs of much of the world. Here it is now--I hope you know some Latin! Most of the quotes are in this once universal scholars language.