Add Additional Logic To Node Save/Submit Process Where can I hook into drupal to modify the value of a specific field just before it is inserted into the database?

For example, lets say I wanted to trigger an email or run an arbitrary piece of code just before the node is inserted into the database?

I've been looking at hook_node_presave and it looks like it will do what I want, but I need it to only apply to one content type.
You can probably use either hook_entity_presave(), hook_node_presave() hook_field_attach_presave(). These hooks are all pretty similar right now. Actually not sure why there are 3 of them :)

Simply add a check for the content type and/or the existense of the field you want to alter.