How do I filter by something like the "Read" field?
Internally, the checkbox fields in Tellico are saved as "true", so if you'd like to filter to show only the science fiction books which you've not read, for example, then you have two rules. Make sure the "Match all of the following" button is checked. Set the first rule to have "Genre" "contains" "Science Fiction" (no quotes) and the second rule to have "Read" "does not contain" "true" (no quotes).
Also, the quick filter in the toolbar will match any field, and if there is a non-word character, the text is interpreted as a regular expression. So if you quickly want to filter your books to show those by Weber or Bujold, then type "weber|bujold" (no quotes) in the toolbar.