Those of you who were paying close attention during my Enneads series know that I like to get a sense of the people I'm having a conversation with before I try to get too engaged. (Who wants to get into the mind of a crazy person?) So let's take a quick look at the authors and translators we'll be looking at before we get started on the Elements proper.
Proclus (412–485) was the last major philosopher of classical antiquity. Our only source for his life is a biography written by his student, Marinus. Evidently, Athena appeared to Proclus in a dream early in life and urged him to pursue philosophy; he did and also worshipped Her particularly. I suppose She indeed had Her hand on his life, as he became the head of the Academy in Athens while still a young man, and taught and wrote prodigiously there for the next five decades—never marrying, just like Her. Soon after Proclus, the institution declined and was forced underground by the (now-Christian) Roman emperors, but it seems clear that much of the philosophic tradition survived and was transmitted to posterity through the efforts of this pious man.
Thomas Taylor (1758?–1835) perhaps needs little introduction around here: he was a tireless student who translated every single scrap of Platonism he could lay his hands on into English and was reviled for doing so, both by Christians (since he was a pagan) and by his fellow scholars (since he was an autodidact). He favored Proclus over all other philosophers and even named his youngest son after him. His translations are fussy and difficult, and his footnotes are never-ending, but he spent an entire lifetime mastering the material, and there's no doubt that he both understood it and lived it.
Thomas Moore Johnson (1851–1919) was a lawyer from Osceola, Missouri, who happened upon some of Taylor's translations while a student and became obsessed with mastering Platonic thought, producing a number of translations and founding journals called The Platonist and Bibliotheca Platonica. Jay Bregman considers him an awkward-but-enthusiastic amateur who nonetheless understood his material, and he played an influential part in the brief-but-brilliant Neoplatonic revival instigated by the Transcendentalists.
Eric Robertson Dodds (1893–1979) succeeded Gilbert Murray (yup, that one) as Regius Professor of Greek at Oxford. I'm generally distrustful of academia post-1930 or so, but Dodds seems to be something of a black sheep: appointed on the recommendation of Murray over more influential peers, a student of Neoplatonism (which made him unpopular), and interested in the scientific study of the paranormal. On the other hand, it seems that he was not completely convinced by philosophy and remained an agnostic observer. So while he may be, perhaps, better than the common academic, it seems an academic he remains, and I should judge his work to require sanity-checking against more invested students.
I have also a couple interesting notes from when I was working my way through Porphyry's Sentences. I favor Thomas Davidson's translation of the Sentences, and this same work was an early and major influence on Thomas Johnson. Second, while I found Kenneth Sylvan Guthrie's translation of that work to be poor, he has an account as fascinating as it is brief of how he was led to translate Proclus by the mystic visions of an uneducated California miner.