manually show Mail

If I Quit Mail and logout or allow laptop to sleep, then Mail does not open after login. If I simply dismiss Mail by clicking the Red X, then close laptop, laptop sleeps, then later open laptop and login to computer, Mail immediately opens in its window.

Yes, thanks for that. Generally I close the Mail window, and very rarely quit the app.

I just wonder why Mail re-opens its window after the computer sleeps. None of the other apps, Excel, Word, Safari, Finder, TextEdit, Preview, do that. If I wish to use an app, I select from the dock, or the Launchpad, or open a document which opens the app.

Thanks to all for thinking about this. The " Sys Prefs>Users & Groups?Login items" was new information for me, thank you especially, BDAqua.

I guess its just one of those things that the apple programmers decided to do for me. So I could easily check my mail when I first login.

I click the red x when I finish using Mail, the window disappears, but I do not Quit Mail.

I checked the Sys Prefs as you suggest. There are no Login Items listed.