“There was no Herodotus before Herodotus.” This little pearl, courtesy of the historical polymath Arnaldo Momigliano (1908–1987), belongs to the class of truly illuminating tautologies. When Herodotus, in the middle of the 5th century B.C.E., composed his “history” of the Persian wars, there was simply no one around to tell him how it was done. The result, as anyone who has lost the thread amid one of Herodotus’s labyrinthine geographic detours knows, is anything but a “history” in the familiar sense of the term — that is, scrupulous, meticulous, and humorless. The project is better understood as an “inquiry” — a more accurate translation of the Greek word anyhow — into the shape of the known world, almost as if such an inquiry were necessary to understand, as Herodotus put it in his preface to the work, “the reason why the Greeks and barbarians fought one another.”

But if Herodotus gives us a map of the known world, we often need a map of our own to follow him. Or, rather, we need 127 maps, which is how many Robert Strassler has included in his mammoth “The Landmark Herodotus: The Histories” (Pantheon Books, 953 pages, $45), a richly gilded new translation-cum-everything-else-you-could-ever-possibly-need-to-read of Herodotus: footnotes, appendices, scholarly essays, maps, guides to the maps, footnotes to the guides to the maps, and a running commentary. When I first read Herodotus as an undergraduate in David Grene’s majestic translation, there was a grand total of eight maps, each more smudged and blurred than the next. They were basically Rorschach blots with captions. No wonder I had no idea what was happening.

Mr. Strassler’s work, by contrast, is like a Global Positioning System for Herodotus’s world. He has made it simply impossible to get lost. Each paragraph has a side note reminding the reader where the story’s at (Greece, Persia, Egypt, an obscure island in the Mediterranean); a chronological signpost reminding him when it’s at (usually between 716 B.C.E. and 479 B.C.E., though Herodotus once warps back to 3000 B.C.E.), and, as if more were needed, a summary of the paragraph itself. When a particular location gets mentioned, a footnote points you to the relevant map, which is rarely more than a page away. There are, remember, 127. And then there are illustrations keyed to the text — of ancient artifacts, monuments, inscriptions, and, in one instance, an embalmed cat. This last is to complement a story Herodotus tells us about the Egyptians’ “intense grief” at a cat’s death: “In whoever’s house a cat dies naturally, those who dwell in the house all shave their eyebrows, but only these; if the dead animal is a dog, they shave all their body and head.”

And what good would a GPS be if it didn’t tell you how far things were from one another? Herodotus uses a number of different measurements: some vaguely familiar (cubit, fathom), most not (palm, pethron, stade, schoinos, and parasang). This last is a Persian unit equal to the distance an infantry could walk in an hour, about 3 1/3 miles, a fact I learned from one of the 21 appendices in Mr. Strassler’s work, this particular one devoted exclusively to weights and measures. This style of measurement apparently survives in modern, rural Greece, where distance is often expressed in “cigarettes” — that is, the number one could smoke along the way.

The translation included here — one feels compelled to say “included” and to treat the translation as a kind of lagniappe — standardizes this spicy measuring stew into rather flavorless “miles” and “inches.” This is surely in keeping with Mr. Strassler’s expressed aim, which is to ensure that Herodotus’s strangeness does not lead the reader to treat his work as “dreary recitation of disconnected incidents at unknown places concerning artificial characters whose names” — and, we might add, ways of life — “cannot be pronounced.” But at times I think that flushing out every last oddity takes away a good bit of the fun. Mr. Strassler is only half right to say that “modern readers who lack special schooling or assistance of some sort understand progressively less … as they proceed into the book and soon find the going arduous and confusing.” A good number, I think, find the going ever more magical, and ever more wondrous. For that set, Grene’s peppery translation — with its perfect ear for Herodotus’s style and a colorful, slightly archaic English — will keep a place on the shelf, slotted alongside Mr. Strassler’s portly cicerone.

Mr. Strassler’s is a first-rate achievement. Nothing is missing. (The “Landmark” of the title refers to the edition’s definitive authority, though it might well refer to the fact that the book is about the size of a small landmark itself.) At times I was tempted to carp that there was too much hand-holding and not enough of what Herodotus himself prized — wide-eyed wonder at the natural world. But that is mostly sour grapes. You cannot help but leave this work deeply edified. That goes for both the large questions — “What was the proximate cause of the Persian wars?”; “How were political institutions in Greece different from those in Persia?”; “How many Persians did the now-infamous 300 Spartans (yes, those 300) really hold off at Thermopylae?” — and for the small ones.

In 513 B.C.E., more than two decades before the blockbuster battle of Thermopylae, the Persians invaded Scythia, the present-day Black Sea region. The Scythians refused to surrender and the two armies arrayed for battle. When a hare ran between the two sides, all the Scythians set off in vigorous pursuit, “shouting wildly and excitedly.” The Persians, seeing this, called off their campaign. This passage has long been my favorite, if for no reason other than that it is utterly mysterious. I still don’t understand it, but I now know, thanks to a reproduction of an ancient gold plaque provided by Mr. Strassler, what a Scythian hunting a hare looks like and, more wonderfully, that this episode “may indicate a favorite Scythian sport, resembling somewhat the furious equestrian game called buskashi still played among riders in central Asia today.” How can you beat that? There was no Herodotus before Herodotus. There was no Herodotus after Herodotus, either, but this gives the Father of History a run for his money.

Mr. Boyle teaches classics at the University of North Carolina at Chapel Hill.