You'll have to check your company HR policy. Every company is different. Same with country. If you mean leave as in quit, you may be entitled to nothing. But then again, it may not be that way, if you give notice. If you mean leave as in retirement, then you might be entitled to it all.

Checking Amazon, there was this one that maybe you might like: The New Executive Assistant : Exceptional Executive Office Management – March 12, 2018
by Jonathan McIlroy (Author)

https://www.amazon.com/New-Executive-Assistant-Exceptional-Management/dp/0648116301/ref=sr_1_1?s=books&ie=UTF8&qid=1535401510&sr=1-1&keywords=The+New+Executive+Assistant%3A+Exceptional+Executive+Office+Management   

Also, "msmarieh" has a good question for you, to see what you want to focus on and learn that.

I see Cloud Computing as the future.  Maybe not for extremely sensative companies, but for other ones.  And personal use.

I started using Amazon's Cloud Music for my music.  What it does is stores my music on their hard drives and I can access it anywhere.  Since my netbok doesn't have a CD drive, I can rip my music at work, put it on the Cloud and acess it anywhere on my netbook (have to be on the internet for this).  And I have an Android phone so I can access it on there too, then I don't have to use my memory on my phone.  Again that takes internet usage, but I have unlimited and only listen during my commute. 

I can see this happening more and more with tablets coming.  These only have a very limited memory (just a bit more then smartphones and a bit less then netbooks).  They also have no CD drive.  Some don't even have a USB drive.  The only way to access anything is either on it's memory or through the internet or some other source.