A very simple alternative to more involved SessionManagement solutions.

By default, Savehist mode saves only your minibuffer histories, but you can optionally save other histories and other variables as well (see option ‘savehist-additional-variables’). You can, for instance save your search strings by setting ‘savehist-additional-variables’ to (search-ring regexp-search-ring).

You can also fine-tune Savehist to save only specific histories, not all minibuffer histories – see the doc string of option ‘savehist-save-minibuffer-history’.

Savehist mode is implemented by library savehist.el, which is part of Emacs 22. A version of the library that works Emacs 20 and 21, as well as 22+, is available here: Lisp:savehist-20+.el.

To activate Savehist mode: (savehist-mode 1)