An example of bad documentation? Unity. It has a list of poorly described methods of deprecated classes. The only reasonable documentation is the community. Docommunitation.

I actually like Unity's documentation... What kind of problems did you have?

@juzles I have no problem right now because after years I have experience and I learned to make sure that the documentation is enough. But I remember at the beginning, the changes of unity versions was traumatic. The classes changes names and methods, some attributes became read only and you had ti find workarounds because the documentation didn't show the new methods to set these attributes, they started to update it after the release. The workaround due to the features that were not available in free version. The networking docs that was totally and slowly rewritten.
Probably I began to study Unity in a time of changes, maybe for that reason I had trouble with the wrong and partial documentation but i know a lot of programmers that changed engine during that time because they had to review all the scripts. Some of these programmers had to rewrite the entire code because of is written in Boo.

Any books? It would seem popular enough to have 3rd party reference books.

I just kind of started with unity and I have to say it's not that bad imo ^^

@LucaScorpion That's the thing, I'm too just starting and wanted to know if something was flawed..

But I got it from the tutorials that the major updates brought breaking changes

I just started poking around unity and I must say the documentation is decent

@sudosuave That's the thing, now it's good but if you started with unity 3 or 4 and now you migrate to 5, that's when it has problems

@juzles yes, that's the problem i dream some night and my dreams are nightmare. I dream about the release of Unity 6.

Hi, I am asked to get tutorials on unity then to make a presentation where I help my coworkers learn working on unity and it should be great one, is there some specific topics that I should focus on in the presentation???

@AboMahdi The Unity team has made some great tutorial videos themselves that cover the basics, those might be useful to have a look at.