Color books have CIE Lab numbers with each swatch that give the device-independent color specification for that swatch. "Device independent" means just that: regardless of the medium or substrate, a 100% opaque sample will have that exact perceived color under standard lighting.
There is only one way to assure totally consistent color, though, and that is to start with a fresh swatch (Pantone, for example, recommends replacing a swatch book every two years to avoid color changes) and compare it with the printed article to ensure a proper match. Large print production facilities have long had dedicated waiting rooms for designers or art directors who fly in to do press checks, for exactly this reason.
You must also view the item under standard viewing conditions. This is an extract from the PIA website that the link points to:
Standard viewing conditions for evaluating color on proofs and press sheets are critical as the metamerism effect of inks will cause some color to appear differently under different lighting conditions. By using standard viewing conditions color will appear the same when viewed at different locations.
Metamerism is a whole subject unto itself, but it's enough to know that even if different pigments/inks/coatings are the exact same color "in the can," the conditions under which they are applied and the actual substrate can produce different appearances when the lighting conditions change. That's why ISO 3664-2009 exists. The full document is downloadable from the ISO or ANSI websites.
The advantage of an official color book like Pantone is that it provides a reference standard that everyone involved with color reproduction can use, no matter where they are in the world and no matter what process is involved.
As a practical matter, you must consult with the provider of whatever article you will be producing as to what they need from you, and you would provide them with the reference swatch they must match. A contract proof, signed off by you and the provider after you have verified the color match, is something you should always obtain where color is critical.
Some cases (self-colored plastics, for example) may require research to produce custom formulations, and the cost of that will be built into the price.
In short, no matter how well your equipment is calibrated and how carefully your studio is set up, nothing substitutes for a good working relationship with your print/product manufacturer and your physical presence on site to verify the color match under standard viewing conditions.
