|I don't have any recommendations mainly because I never read any books related to Excel.|
I just lurked in a few Excel related forums, used Google a lot (still do) and try to find answers to questions by trial and error.
It's amazing how smart you can sound if you can find something close in other forums via Google and then modify it to fit the specific question asked. ;-) Most times I'll give credit where credit is due or even point the OP to the website where I found the answer.
For example, instead of asking here how to deal with the #N/A errors, you could have just Googled something like eliminate isna and gotten lots of hits. Reviewing some of those hits would not only have provided the answer, but you might have run across some other pearl of wisdom that you can put away for another time.
In other words, I don't always know the answers to the questions in this forum, but most times I know how to find/tweak/figure out the answers.
The journey is half the fun.