The William E. Boeing, Sr. Papers are comprised of visual and textual materials related to the personal life and career of William E. Boeing, Sr. (WEB). The collection holds textual materials, such as correspondence and philately, business-related materials, and clippings and ephemera as well as photographs and illustrations, circa 1783-2008. Major areas of interest include family photographs and extensive personal and business-related correspondence, especially during the founding of The Boeing Company, and several rare pieces of aerophilately. In most instances, materials have been collected by William E. Boeing, Sr. although a few items were likely gathered by family members after his death.

The collection has been arranged into two series, visual materials and textual materials, which have been further arranged into subseries. Materials are arranged chronologically within subseries. See the Note on Arrangement for more details.

Series I, Visual materials, circa 1783-1975, consists of three subseries: photographs, balloon illustrations, and artwork. The photographs subseries includes approximately eighty photographic images and includes primarily vintage prints, two cartes-de-visites (card photographs), and a few modern reprints. It is further divided into six subseries: family and personal, lumber industry, aircraft and aircraft-related, boats (yachts), people, and Alaska hunting expedition. Sizes vary from 3x5" to 11x17". Many photographs include brief captions providing contextual information such as name, date, and/or location. Some duplication occurs.

The family and personal subseries, circa 1868-1955, includes two cartes-de-visite photographs depicting Wilhelm and Marie Boeing, WEB's parents; black-and-white photographs of WEB and family members, such as his sister Caroline and his Uncle Rudie; casual snapshots and portraits of WEB; a black-and-white photograph of a snow-covered "Aldarra," WEB's Seattle home; and portraits of WEB's racehorses, including "Porter's Mite."

The lumber industry subseries, circa 1903-1915, includes black-and-white photographs of WEB and unidentified men in various logging and lumber yards.

Within the aircraft and aircraft-related subseries, circa 1909-1940s, are black-and-white photographs of WEB's Martin Seaplane in the air, on the water, and in the hangar. WEB is often in many of these images. There are also assorted images of a tent hangar on Lake Washington; two images including Eddie Hubbard with Boeing Model C; various images of other aircraft, including a Loening C2, Boeing P-12, Boeing Model 200 Monomail, and Boeing Model 204A; and WEB's Douglas DC-5 "Rover," which includes an inscription from Donald W. Douglas.

The boats (yachts) subseries, circa 1917-1930s, is comprised of a handful of black-and-white pictures of yachts on the water, including WEB's "Taconite." WEB is included in two of the images in this series.

Included in the people subseries, 1915-circa 1950s, is a black-and-white photograph of Floyd Smith, a portrait of Clairmont "Claire" L. Egtvedt inscribed to Bertha and WEB, and two images with unidentified men, likely related to aviation. One of the images shows two men reading a [teletype?] tape in what looks to be a navigational room and the other image shows a man in front of a radio control panel.

The Alaska hunting expedition subseries, circa 1916-1920, contains black-and-white photographs from a trip that WEB had planned to attend but did not; it is unknown who took the photographs. In Box Two, Folder 56 a letter, dated 1916, mentions a "trip to the Arctic that he [WEB] will likely forego," which may be referring to the trip where the photographs were taken. Note that some images depict graphic scenes, including dead animals and burials. Most of the images depict hunting scenes, such as walrus and polar bear kills, animal skins drying on a hillside, and a group of people posing with hunting implements. There are also a few images of Alaska Natives, as well as a wooden structure and a shrouded body on wooden poles, likely as part of a funeral.

In addition to the photographs there are a set of balloon illustrations, circa 1783-1850s, that contain thirteen prints of varying types, including engravings, etchings, and letterpress prints. It is likely that these were collected by WEB. Most have two copies. Several have tags and/or captions which provide context. The images depict early aviation balloons in various scenes, such as in flight over cities and landscapes and in ascent or descent status. The dates given in the inventory reflect the dates of the events illustrated, not necessarily the dates the prints were made. Also present are a few related documents. One piece of artwork, is also present: a painted certificate commemorating the resolution to name Boeing Field after WEB from June 20, 1928.

Series II, Textual materials, 1910-2008, is comprised of three sub-series: correspondence and philately, business-related materials, and clippings and ephemera. The correspondence and philately subseries (circa 1910-1963, bulk dates 1910-1929) is by far the largest and holds assorted correspondence in the form of letters and telegrams, the bulk of which is correspondence between WEB and G.C. Westervelt, particularly during the early years of Boeing Aircraft Company. Note that Westervelt's handwriting is quite difficult to read.

Virtually none of the correspondence is accompanied by the original envelope and none include original enclosed materials. Many letters sent on behalf of WEB, when out of town, include an illegible signature but are likely by Edgar Gott based on replies to these letters. Major topics include the company's early aircraft and searches for pilots, contracts with the military, and partnership with University of Washington in regard to the construction and use of a wind tunnel. Additionally, the birth of air mail is reflected in correspondence and by the many pieces of aerophilately, 1918-1953. This material is primarily in the form of air mail covers [envelopes], although there are a couple of airgrams and postcards as well. First flights, first issues, and commemorative pieces form the bulk of the philatelic material. Some air mail covers include air mail stamps, although not all do. Most of the correspondence with the air mail pieces is simply a quick note for the sake of creating a collectible cover.

The business-related materials subseries, 1917-circa 1965, is a relatively small set of items consisting of documents created by The Boeing Company at various points, including meeting minutes, company news briefs, and an aircraft model chronology sheet. There is also a list of Boeing Company promotional films available for loan to outside agencies. Note that the company name changed slightly over time and this is reflected in folder titles. Some of the material is referenced in the correspondence sub-series.

Lastly, the clippings and ephemera subseries, 1910-2008, holds original and photocopied newspaper clippings from an assortment of newspapers, including the Seattle Times,Seattle Post-Intelligencer, and the Wall Street Journal, among others. Topics include aviation in general, Boeing Company, and WEB. Other materials include a Boeing Air Transport passenger ticket, a 1927 program reception booklet for Charles Lindbergh, a blank "Nookey ration card," and a November 1956 leather-bound issue of Boeing magazine with a memorial article about WEB. Additionally, there is a photocopy of a map which depicts the Boeing family homestead in Germany and an undated caricature of WEB flying a biplane.