Books on investing, many are elusive/incomplete.

The reason is that investing has many different approaches, ways and disciplines.  

Like value investing, momentum-investing, high yield investing, defensive and non-defensive investing etc... But for sure one should never confuse investing with trading.  Unless you are a professional trader, trading is always a form of speculating.  However, some trading around a well chosen good stock, on part of one's position, can be profitable.  As if you get stuck, you still own a well chosen stock/company and if it runs away, well at least you nailed down some profits and were rewarded.
Realize, investing is most always messy and confounding and complex and our understanding even of fairly simple things, is constantly evolving. The best we can hope for is reducing uncertainty by knowing/understanding as much as we can, but no more... i.e. beware of "analysis paralysis", on what we invest in.  Many stock analyst are poor investors as they just too close and always see the downside.  Engineers can be poor investors as they often work in an environment of seeking certainty, which stock investment never is. I think analogical reasoning is a key skill to have to be a successful investor.

The other thing, rarely mentioned, is much of financial investments are dominated by mega- big institutions and funds, which can only consider very highly-liquid trading stocks!  Hence, there is much value in those much neglected secondary smaller cap. stocks, which however are rarely analyzed by brokers -as these mostly cater to institutions and traders, yes for more commissions.   So, some smaller mid cap stocks can be "diamonds in the rough", but at the same time far less information available on them. But then again an old Wall Street saying comes to mind  "an investor bargain which stays a bargain is no bargain".  Not least many are so-called "wall flowers", or "bad apples",  which look good "on paper",  but are stocks whose prices' never go anywhere.  Some are cheap for good reasons, not least a bad history of corporate-governance or even worse.

Best Regards,