Any suggestions on a quality book?
My first response is to suggest Hornady's
Manual of Cartridge Reloading, which is around $35Buck$ or so. It covers pistol and rifle metallic cartridge reloading (shotgun hull reloading is a separate issue).
I recommend Hornady's because it has an excellent discussion of interior ballistics; that is, what's going on in the firearm from the time the trigger is pulled until the bullet leaves the muzzle. Read that section (with pictures) 3-4 times and you'll have a new appreciation for what happens hidden inside the action, chamber, and barrel.
As LeeM says above, later on you'll want to add another couple of manuals (Lee, Speer, Barnes, Lyman, Berger, etc.) because not all manuals contain workups for all cartridges at all bullet weights and all velocities with all powders. Also, they rarely agree across the board, so it's nice to have a means to cross-check the reloading data and ensure that your reload is in the zone of safety.
YouTube videos are available. Some are good; many are not. The production quality often suffers, as might be expected, since the producers are usually amateurs, like all the rest of us. And the narrators tend to drone on somewhat without providing any useful information. You'll have to use your judgment on the videos by cross-checking with other videos, plus your own experience.
The various powder and bullet manufacturers post their reloading data on the web. However, they usually offer little or nothing in the way of reloading process information.