Even though he doesn't follow our modern rules of history-writing (and neither do I, for that matter), he is careful to tell multiple versions of the same story and let the reader decide which one is true. He does seem to utterly believe in the intervention of gods in human affairs (something his successor, Thucydides, clearly does not), but otherwise is quite a sober relater of events, many of which are obtained from eyewitness accounts. They don't call him "The Father of History" for nothing.
Here's Grace Tjan's review:
What I learned from this book (in no particular order):
1. Ancient Greeks are quarrelsome and love to waste each other’s city-states for the pettiest reasons.
2. From all forms of government known to man, democracy is the best. Tyrants and oligarchs suck.
3. The Persian Empire is a mighty barbarian nation, but being cowardly, effeminate and slavish, it is eventually defeated by the quarrelsome but brave and civilized Greeks.
4. Among the Greeks, the Spartans are the bravest.
Gerard Butler with a six-packKing Leonidas and his 300 Spartans heroically perished in the battle of Thermopylae. They also have the particularly icky custom of marrying their own nieces.
5. The Delphic oracles are 100% accurate, except when someone manages to corrupt the Pythoness. The Gods are, however, a jealous sort and would strike any mortal who has the presumption of calling himself happiest on earth. Therefore, one should call no man happy until he is dead.
6. Egypt is a country of wonders, but its citizens’ customs and manners are exactly the reverse of the common practice of mankind elsewhere. For example, the women there urinate standing up, while the men sitting down. The country also abounds in strange fauna, among them the hippopotamus --- a quadruped, cloven-footed animal, with the mane and tail of a horse, huge tusks and a voice like a horse’s neigh.
7. The Scythians are a warlike nation that practices human sacrifice. The Scythian soldier drinks the blood of the first man that he kills in battle and cuts off all of his enemies’ heads, which he must show to the king to get his share of the war booty. They also like to saw off their enemies’ skulls, which they make into fancy gold-plated drinking cups.
8. The manners of the Androphagi, being cannibals, are more savage than those of any other race. Darius the Persian smote them.
9. The Atarantians, alone of all known nations, are destitute of names. The title of Atarantians is borne by the whole race in common, but the men have no particular names of their own. They also like to curse the sun because he burns and wastes both their country and themselves.
10. In the Indian desert live ants that are larger than a fox. They like to throw up sand-heaps as they burrow, which are full of gold. This is why India is so rich in gold. In Arabia, there are sheep that have long tails, so long that the shepherds have to make little trucks for their tails. Really.
Herodotus is a consummate storyteller who had a fine eye for the fantastical, although to his credit, he always qualified his more improbable assertions by stating that they are based on hearsay or other sources that he could not wholly verify. Much of the pleasure of reading his book is found in the lush descriptions of long lost nations and their exotic customs. His 'Histories' does not concern itself solely with history in the modern sense, but it is also a book of travelogue, ethnography, zoology, geography and botany. He is an excellent raconteur, almost always entertaining, except when he drones about speculative geography. We can easily imagine him, a man of seemingly inexhaustible curiosity, interviewing Marathon veterans for firsthand battle accounts, or interrogating Egyptian temple priests about their country’s history and religion. History for him is not a dry recitation of facts and dates, but an intensely human story acted by a vast cast of monarchs, queens, warriors, tyrants, gods and ordinary citizens. Regicides and rebellions are caused by personal passions, such as in the stories of Caudales and Gyges, and Xerxes and Masistes. Dreams compel Xerxes to invade Greece. Divine intervention decides the course of epic battles.
A skein of tragedy runs through the historical drama that he narrates. The gods are so capricious and jealous that “one should not call a man happy until he is dead.” Xerxes, on beholding his massive force on the Hellespont, laments that “not one will be alive when a hundred years are gone by.” Yet while man lives his short existence he is capable of epic deeds, and Herodotus chronicled them all.