This a translation from the Chinese 2nd century Can Dong Qi, the earliest text on transformation, with original Chinese commentaries. The author's own commentary explains the intricacies of the text's allegorical symbolism for the Western reader while the text itself and the original commentaries are full of practical information and advice about the human transformation process.
I have just finished the Fabrizio Pregadio's translation of the Can Tong Qi (entitled The Seal of the Unity of the Three [shortcut for title: "SU3"]) and wanted to compare it with Bertschinger's [SEL]. The first observation is that SEL is much easier reading for a nonspecialist, whereas SU3 seems presented more like a doctoral dissertation. Both translators are sensitive to the elliptical, cryptic, layered nuances of the original text, and admit that in some cases, different translations to English are possible.