Hi, For this question I''m going to assume I have a simple one to many relationship between person and title, where a person belongs_to :title and a title has_many :people. Initially, to provide a list of titles for a given person I used the following. <%= collection_select :person, :title, @titles, :id, :description %> This caused a problem when creating the new person because it was expecting a Title object but was getting a number. I then went down the route of changing the collection_select to something like the following. <%= collection_select :title, :id, @titles, :id, :description %> This meant that the title didn''t automatically get assigned to a person on creation, so I was doing an additional db lookup to get the title (Title.find(params[:title][:id]) and then assigning that to a person. This is how things stayed for a while until I suddenly realised that if I changed :title to :title_id in the original collection_select I had that the id of the selected title would just get assigned automatically on person creation. This also means that the correct list item is selected when editing a person (previously I was returning a Title object from the db in order to get the selected item). I guess I''m really wondering whether this is the intended use of collection_select and the fact that it took me so long to click is just indicative of my naivity with Rails? Chris