@
greenrun -
above replies - and
Identify a representative sample of the books, with & without metadata, the different formats you have etc, and get them into a library and have a play around with it, be prepared to throw it away and start over;
First things I would get right for each book is the Author, Title and ISBN. Then decide (and play with) things like Author handling, particularly sorting, Initials, Tag browser layout etc and set the appropriate options. You can change options later, but if you take a bit of time exploring what's available now, then you will have an appreciation of what's possible when you want to change something.
Also consider having a separate library into which you do the initial importing, there you can get the basic metadata correctly set up, and then move (right click Copy to Library) to the good books library
There are lot of features in the right click menu's, you wont remember what they all are - but you'll often find that what you want is under your right mouse button
Another issue to consider is how to detect and handle duplicate books - importing into a separate library first will give you of the possibility if using the Find Duplicates plug in feature of comparing books in two different libraries.
As well as the base product there are a lot of very useful Plug-Ins - when looking for a feature first look in the
calibre User Manual next look in
Index of plugins
I would import the books in batches and get each batch into shape before starting on another batch - the size of the batch will depend on what sort of 'mess' I was starting from and the time I could allot to the task.
One the first things to do is to establish a backup regime for the library(ies) you create and make sure you know how to recover a library from the backup. I suggest an incremental mirror backup - Free File Synch is popular with many calibre users. I backup at least once a day. I've never had to restore more than a single book - and the need to do so was invariably and entirely my own fault
BR