Learning music theory !
I am a beginner violinist and want to learn music theory. About harmonics, tuning types, chords, etc I don’t know much but basically what is taught at college. So which books can cover these topics about music in general and in depth ?
The Violin Lab has a nice music theory/note reading course taught by Beth Blackerby. This is a standalone course that is separate from her ongoing violin lessons. It's a well spent $39 and you keep access to the materials - and any she adds to the course - in the future. It's a nice starting place, and I took it a couple years ago.
@carmen this website is nice. Does it contain everything From A to Z that I need to become a good violinist.
Beth's "Notes and Theory" lesson is separate from her basic lesson - it's meant to be standalone - you don't even need to be on her subscription lessons to purchase this package (and I am not).
The later chapters of the website are perhaps overkill for someone who is mostly interested in PLAYING classical music that is already written.
From your initial message it was not quite clear to me what you know, and what you want to learn. I suspect that there may be a language barrier.
I always go for cheap. Sometimes cheap is good. Eric Taylor The AB Guide to Music Theory is cheap and good.
Gordon's suggestion is pretty good. The book is aimed at sort of kids/teenagers, so it'll be easier to understand
I've tried reading Piston. It's impenetrable to the amateur. It may be a fine textbook to use in a course where you are being taught by a master of the subject. There are many books like that in my field (chemistry) that professors say are wonderful, and from which we learned certain subjects, but our own students loathe them.
I second what Gordon suggests. Adam Taylor's Pink and Blue theory books are fantastic, and I also like the workbooks that he has also written. With those resources you can learn and apply a lot of music theory.
Michael Berger (above) gave a sort of "spacecraft flyover" of resource types in the field of "music theory." But that is what the field is. What one gets in most beginning books purporting to explain music theory is the "language of Western Music," the "Circle of Fifths," etc.: how to read notes on a 5-line staff, key and time signatures and what it all means to a player. This will certainly get you into and through playing violin from written music. I know this is called "Music Theopry" but I think of it as "Western Music Rules."
Psychophysics and music cognition are now making their way into music theory departments. Previously you would take the courses in a science department.
The word "theory" is used differently in science from everyday use. In everyday use "theory" is stuff you need to learn with your brain and "practice" is what you need to learn with your hands (or more generally with your body). "Music theory" in everyday use is very much the everyday kind of theory, everything from reading notes to harmony. It is the brain part of the tool kit musicians need to do their jobs. And this is doubtless what the OP had in mind.