Books and magazines:
Village Press publisher of Home Shop machinist, Machinist workshop, digital Machinist, and Live steam and Model railroad Magazines. They also publish project books and collections of article as well as selling a few select books published by others on metal working.
Another fine publication published by Mike Remus
Nation Builders books From steam engines to Spacecraft
Tony mostly resells books but does self publish a few.
All of the above folks come to the major shows and support this hobby.
And I would be amiss if I did not include
Model Engineer and Model engineers workshop. A great resource for those in or near the UK
Also Engineering in miniature Tee publishing
And for the Ausies and NZ folk
Text books can also be a good source of basic knowledge
Machining Fundamentals, 8th Edition
Exploring Metalworking, 5th Edition
And last but not least Industrial press. As the name implies these books are aimed at industry, professional machinists, CNC Programmers and engineers.
These guys have published the machinery Handbook since 1915. They do also offer some quick and ready references.
And as said before a copy of a machinery handbook is an almost must have reference. But and older edition will likely do.
And remember book prices can vary greatly from various sellers and outlets shop for the best price. Outdated editions can often be had cheap and are useful in the home shop.