Amazon is the most obscure large company in the tech industry.

It isn’t just secretive, the way Apple is, but in a deeper sense, Jeff Bezos’ e-commerce and cloud-storage giant is opaque. Amazon rarely explains either its near-term tactical aims or its long-term strategic vision. It values surprise.

To understand Amazon, then, is necessarily to engage in a kind of Kremlinology. That’s especially true of the story behind one of its most important business areas: the logistics by which it ships orders to its customers.

Over the last few years, Amazon has left a trail of clues suggesting that it is radically altering how it delivers goods. Among other moves, it has set up its own fleet of trucks; introduced an Uber-like crowdsourced delivery service; built many robot-powered warehouses; and continued to invest in a far-out plan to use drones for delivery. It made another splash last week, when it showed off an Amazon-branded Boeing 767 airplane, one of more than 40 in its planned fleet.

These moves have fueled speculation that Amazon is trying to replace the third-party shipping companies it now relies on — including UPS, FedEx and the United States Postal Service — with its homegrown delivery service. Its logistics investments have also fed the general theory that Amazon has become essentially unbeatable in American e-commerce — no doubt one reason Walmart, the world’s largest retailer, felt the need this week to acquire an audacious Amazon rival, Jet.com, for $3.3 billion.