Photographer and postcard publisher Alexander J. "Zan" Stark (1889-1967) moved to San Francisco ca. 1914 (Xan Stark, Alta Studios, 1271 Mission) and then to Mill Valley in the mid-1920s (Zan of Tamalpais, 324 Miller Avenue). He produced thousands of postcards from the early 1930s through the early 1950s, primarily b+w real photo postcards (RPPCs). Zan photographed extensively throughout northern California and beyond. Online Archive of California gives a brief biography and references the Stark collection at Stanford (over 3000 items, but no online items as of 10/2020). A postcard.org article by Frank Sternad discusses Zan and his work in detail.

My postcard collection focuses on cards from 1915 and before, so it includes only a few Zan cards (shown below). But I see a lot of Zan's cards when I browse postcard sites, and I invariably admire his work. He has a wonderful eye and his postcards have a very distinctive look: b+w, caption in script in one corner, "Zan" and stock number in opposite corner, vanilla RPPC back with no information.

Courtesy of: https://www.nesssoftware.com/www/sf/sf_postcards.php?id=Zan&select=Lists

More about Zan postcards... https://springsmuseum.org/wp-content/uploads/2017/12/zanmonograph.pdf

OAC = Online Archives of California: I believe this is the same as the Stanford collection, mentioned above.

Description
The collection comprises over 3,000 real photo postcards and photographic negatives, a large portion of the output of Alexander J. Stark, a Mill Valley-based photographer who published under the name " Zan." Postcards and photographs focus on Northern California, circa 1935-1955, and depict scenes of nature, travel destinations including vacation & historical attractions, architecture, bridges, and various street & cityscapes. All images are in black and white, and most are captioned. Many of the postcards appear to have been removed from Zan's scrapbooks, and for the most part his ordering has been retained. However, most numbered series contain gaps or numbers used more than once, and images are also re-used with new numbers in some cases. Postcard numberings also may not relate to their respective negative, if present. More detailed descriptions of the postcards can be found below.
Background
Alexander J. " Zan" Stark (1889-1967) was a Michigan-born photographer who moved to San Francisco, California around 1914, where he established a photography and lantern slide business under the name Xan Stark, Alta Studios. In the early 1920s Stark produced at least three volumes of photographs of female (banned word) in an "Alta Art Studies" series. Stark moved to Mill Valley in the mid-20s and operated a studio at 324 Miller Avenue. He produced thousands of photographic postcards under the name " Zan of Tamalpais" through early 1950s. Zan photographed extensively throughout Northern California, as well as in Oregon, Nevada, Arizona, and elsewhere. He was the official photographer of the Redwood Empire Association beginning in 1936, and many of the postcards bear the Association's name. Much of his work appears to have been on a promotional basis, capturing roadside attractions, hotels, resorts & restaurants, and natural wonders such as Yosemite and the redwoods. Along with his son, Stark was also involved with local politics and journalism. Around 1953 Stark moved to Boyes Hot Springs where he remained until his death in 1967.