I’ve been working on assigning dates to Detachable Starched Collars I own with information I’ve found through advertisements in Newspapers.com , Patent Records, clipped ads for sale on eBay, etc but was looking for more. Now I have run into some online copyright expired books and magazines that I think may help with doing this also. Many later collars have a lot of information about brand names, place of origin and manufacturing company names printed on the inside that help with this, and these books seem like they may be useful for narrowing down dates on collars by tracking the history of the name changes in the companies. Collar companies in the US were constantly eating one another, combining, breaking apart and vanishing through the whole second half of the 19th Century and first half of the 20th Century. Cluett for example went through all sorts of changes that may help date their collars. Some parts of these books seem to track a few of the dates of these mutations. If there is someone with better obsessive compulsive genes for working on forming this into cheat sheets and databases of collar names and dates faster, feel free to try. Meanwhile, if you are looking to “date” your own collars this is a good place to start.