I've started to learn independently some Chinese (on printed material mainly) but a friend who has studied the language at University level suggested I learn the radicals as a necessary start. A bookseller also had suggested this a while ago and sold me a (lovely) book about radicals (that the bookstore itself, Librairie You Feng in Paris, printed). I will be starting a course soon (not knowing where it will take me) but is this a reality? Should I really try to memorize the 214 basic radicals? Thank you for your help!
I feel like this question could elicit subjective and open-ended answers, but here goes anyway ...
In Beijing, one of the classes I had was a dedicated 汉字 (Hànzì, Chinese character) class. In it, we were learning the most common radicals, and some word examples that contain that radical. We learnt how, often, the meaning is conveyed by the radical and the other portion is often a pronunciation component. I found this to be enormously helpful; even without recognising some characters, I could sort of guess at their general meaning and, with the context of the sentence, understand what was going on.
Contrasting this to the general classes I attend at 孔子学院 (Kǒngzǐ Xuéyuàn, Confucius Institute) where they do not teach you any radicals, simply tell you to learn and remember the new words yourself, I notice most classmates struggling to remember "which little bit goes next to the bigger bit." I found my prior knowledge of some radicals helped me learn the characters quicker than my classmates, and my belief that they are of importance continues to allow me to learn previously-unknown-to-me radicals and characters faster as well.
They are important. They are necessary to learn. However, whether you specifically set out to learn them first, or if you gradually learn them and get a feel for them as you continue your education ... that part is up to you.
I, for one, would definitely recommend to keep them in mind, but not necessarily learn 214 common ones before learning any whole characters. I would probably learn a character, figure out what the radical stands for, see if there are other variants (like 心 xīn: heart radical has a couple of different forms) maybe look up a few other characters with that radical, then press on with the next character in your book. Rinse and repeat.
Note, there will be certain characters where the radical doesn't appear to provide any understanding of what the character means. That's just how it goes sometimes: you might think it's stupid and it should have [x] radical instead of the [y] radical that it has, but you could say the same of any language really: some bits are just nonsensical, and you just have to remember it but not necessarily understand it (the best lesson my calculus teacher ever taught me: "You don't have to understand it, you just have to know it." took me from a C to an A.)
From my experience, knowing the radicals does help to categorise characters in your head and it's somethign you can hold on to. However, I have no learned them in isolation, each time I learn a new word I make sure to look up the word in the dictionary which mentions the radical.
I don't think it's helpful to learn 200+ radicals off the bat. For one some are not that common, second, some don't have a meaning or the meaning is not straightforward, and third, only by seeing them often will you retain them. Start with simple ones and try to find some words you alraedy know in the dictionary look-up table.
It is also true that not all dictionaries even use the same radical look-up table, and some dictionaries associate a different radical to a different character I noticed, it's rare but it does happen.
The importance of looking up words in a dictionary by using the radical look-up table, while still important, has dimished somewhat with the use of technology, you can often copy paste the word and many smartphone apps can recognise characters with the built-in camera.
The main challenge for me in learning Chinese is staying motivated by having fun, learning radicals in isolation is not fun, after a while you will pick up on them either way, they will end up in your wrist memory from writing the characters, just do what you think is best, as long as you're having fun learning.
Try to do things in order of importance, many people are able to read Chinese but can't write it, how important something is is all relative, radicals are a "hook" to character recognition, but you don't need to know them all to read Chinese, it is just handy for dictionaries and to categorise them.
I am learning some written Mandarin through memrise.com, and their approach when introducing a new word, is to explain all the different part first, so you end up learning all the radicals naturally. I think it works better than learning them in isolation, because you can immediately relate to how they could be used.
Being able to recognise radicals is very helpful; they sort of provide visual cues for what a character mean or sound like (but there's also traps!). That said, I don't know how useful specifically trying to memorise the radicals is. I'd thought you would naturally pick it up after you've learnt a few characters.
I think knowledge of radicals is inescapable as many dictionaries have at least one index organised around radicals and stroke count. I find it easier to learn characters (and related characters) using radicals. These relations between characters assist in overall comprehension and multiply the number of characters one can recognise quickly.
Looking at radicals and characters should not (in my opinion) be a separate exercise. I've taken courses designed to study characters and their etymology, which really helped me learn grammar more easily. Zhongwen.com gives a good online sample of the radicals and how they can be used to access related characters. I would not put off learning either but rather suggest you supplement your coursework by continual self-study of the radicals.