Did you install the northwind sample? If not, do so. Look at that, you can see how a lot of stuff works.
From what you said about things like average books read per month, you don't need the day of the month. Suggestions about using a number are good. If you don't want to parse the year and month out of a single number, use 2 numeric fields for month and year. To extract the stuff you already put into the date field and populate these 2 new ones, add the fields in design view, make an update query that uses the month() and year() functions.
There are other correct ways to do this. I suggest this approach because I think you'll be better off having separate month/year fields than having to extract them from one field.
I can't recommend an access book, I haven't bought one since access 2.0 (which was far and away the best version, after they purchased foxpro for its index technology and before too much fluff and cruft were added). Go to the bookstore of your choice and browse. At this level, it probably doesn't matter what book you look at.
Access is OK for what you're doing with it. Don't try to use it for real in a multiuser environment though.
Also, what Conrad said.