Update: In iTunes 12.4, the procedure is different. Press Command-J to display the View Options window, where you can more easily check and uncheck the columns you want to view.
If you display content in iTunes using one of its list views – Songs view for music, Movie List view for videos, etc. – you can choose which of the many columns the app displays. Each of these columns allows you to view certain tags, such as a track’s Name, Artist, Album, etc. And clicking a column header allows you to sort your music: by Artist, Album, Date Added, and more.
To select columns, open the View Options popover at the right of the navigation bar (or press Command-J). Then, click Show Columns to display the Columns pop-up menu . Each entry lets you show or hide columns; you see different options depending on which view is active in iTunes.
In previous versions of iTunes, this menu was a palette; a kind of floating window that had checkboxes, so you could select and deselect columns easily. Now you have to click to display the menu, then click a column’s name to show or hide it. In addition, many columns are in submenus, as you can see at the bottom of the menu, and this menu disappears each time you select an item. So if you want to show or hide a number of columns, you’ll be doing a lot of clicking.
You can also show or hide columns by Control-clicking any column header and choosing a column name; a visible column has a check mark next to its name in the contextual menu. Unlike the menu in the screenshot to the left, there are no submenus. But you have to individually choose to show or hide each column by selecting its name, and this menu is quite long (there are a few dozen columns you can display).
After adding columns, you may want to reposition them by dragging them left or right in the column header area, and resize them to show all the information they contain or to make them fit in the window.
One way to resize columns is to Control-click a column header, then choose Auto Size Column or Auto Size All Columns. iTunes fits the size of one or all visible columns to hold the longest text that they contain. Or, drag the divider between any two column headers.