Originally Posted by chaley

Calibre does not support the 'wildcard' mode that MS uses in some places. If you want to get that functionality, you must use regular expression mode. No way around that. Note that the regex for 'anything' is ".*" (without the quotes). "*.*" is an illegal regular expression.

Search and replace (S/R) specially handles fields that contain multiple values, such as the authors and tags fields. Each author/tag is processed individually, not as a single value containing all the authors/tags.

S/R can treat multiple-valued fields as single values, but it is another step up in complexity beyond regular expressions. You must use 'template' as the source field, provide a template (in calibre's template language) that generates the value you want to work with, provide appropriate search & replace values, then set the destination field to where you want the information to go. For example, to change all authors of a book to the value "Someone Else", you would (all without the quotes):
- set the source field to template
- set the template to "{authors}"
- set the search string to ".*"
- set the replace string to "Someone Else"
- set the destination field to Authors.