You can open the History in the sidebar via View > Sidebar > History (Ctrl+H)
Press F10 or press and hold the Alt key down to bring up the "Menu Bar" temporarily.
You can find toolbar buttons to open the bookmarks (star) and the history (clock) in the sidebar in the toolbar palette and drag them on a toolbar.
Firefox 4 has two bookmark buttons with a star in the Customize window.R
One star button has a drop marker that open a Bookmark menu.
The other star button without the drop marker opens the bookmarks in the sidebar.
Open the Customize window via "View > Toolbars > Customize" or via "Firefox > Options > Toolbar Layout"