Understood.
That’s what I’m asking you! 
I always seems to struggle understanding how spiders work…
First of all, what is the difference between a “bot” and a “spider”?
This is how I think it works…
Google lands on your Home Page, and its spiders look for all links on the home page. It then navigates to each of those linked pages, and on each of those pages repeats the process.
Now what I am failing to understand is how Google handles dynamic links and pages.
You see, most of my client’s website is dynamic and database-driven.
For instance, let’s say a person went to the “Outdoors” section. My PHP would go to the database, and find links to all current articles and content about “Outdoors”. So the links would be built by PHP.
In other places, I have lots of pages related to a users account: Reset Password, Update Profile, Check Balance, Manage Friends, etc.
In those scenarios where web pages are not hard-coded, it is unclear to me what Google can and cannot see.
It is also unclear to me if I would need things like Keywords and Descriptions for the pages? 
Right, and so I want to control as much as what Google has to show and say about my client’s website. (And to your earlier point, I don’t think “organic” keywords and descriptions are enough!)
The goal is to give people who search for my cleint’s website the most accurate and relevant material possible. (I just HATE website that don’t use < title > tags or where search results come up and it is some cryptic text - sometimes even with markup tags - to where you don’t know what the page is until you click on the link.)
This is not about playing the SEO game. Rather, it is about taking all of my hard work developing things, and all of my client’s hard work writing articles and product dscriptions and so on, and making sure Google displays it in the best light possible.
For my “article.php” page, I believe I put in PHP fields for the meta Keywords and meta Description so that depending on the article, it will pull appropriate words fro the database.
But for things like a log-in page, or a member profile or a change email page, and so on, I am unsure what Google even sees, and if it makes any sense to have to add these meta tags.
See my confusion?
Thanks.