1.  Marriage Record:

2.  Illinois, Cook County Birth Certificates, 1878-1938 (online at familysearch.org):

Name	Charles Haslup Straub	Walter Morris Straub
Event Date	06 Dec 1919	06 Dec 1919
Event Place	Chicago, Cook, Illinois	Chicago, Cook, Illinois
Gender	Male	Male
Father's Name	Walter M Straub	Walter Morris Straub
Father's Age	32 years
Mother's Name	Margaret Hamlup	Margaret Tinsley Haslup
Mother's Age	20
GS Film Number	1309347	1309347
Reference ID	43329	43329

3.  1890 U.S. Census:  the 1890 Census Population Schedules were destroyed.

4.  1900 U.S. Census Every-Name-Index/Images (online at Ancestry.com):  Walter M. STRAUB (æ 14, b. Jan 1886, PA) is living in Pittsburgh, Allegheny Co., PA, with his parents (q.v.).  Margrett HASLUP (æ 10/12, b. Nov 1899, MD) is living at 1032 Hopkins Ave., Baltimore City, Baltimore Co., MD, with her parents (q.v.).

5.  1910 U.S. Census Every-Name-Index/Images (online at Ancestry.com):  Walter M. STRAUB (æ 24, b. PA) is living in Pittsburgh, Allegheny Co., PA, with his parents (q.v.).  Margaret T. HASLUP (æ 10, b. MD) is living at 2125 N. Calvert Street, Baltimore City, MD, with her parents (q.v.).

6.  World War I Selective Service System Draft Registration Cards, 1917-1918.  Microfilm Series M1509 (4277 rolls), National Archives and Records Administration, Washington, DC (card images and index online at Ancestry.com):

Microfilm Roll	1684136
Name	Walter Morris Straub
Permanent Home Address	2125 N Calvert St Balto Md
Age in Years | Date of Birth	33 | Jan 6 1885
Race	White
U.S. Citizen	Native Born
Present Occupation	Distributer
Employer's Name	?m. Sugar Refining Co
Place of Employment	505 Emmerson Lower Bldg
Nearest Relative Name	Wife Margaret Straub
Nearest Relative Address	2125 N Calvert
Signature	Walter Morris Straub
Height (tall, medium, short)	6.2
Build (slender, medium, stout)	Medium
Color of Eyes | Color of Hair	Blue | Brown
Registration Location	Draft Board 12, Baltimore
Date of Registration	Sep 12, 1918

7.  1920 U.S. Census Every-Name-Index/Images (online at Ancestry.com):  I can't find Walter & Margaret or their children, anywhere, and I really looked.  Margaret's parents are still living at 2125 N. Calvert Street, Baltimore, MD, but Walter & Margaret are no longer with them. 

8.  Bronx County, New York, Divorce and Civil Case Records, 1914-1951, 1961-1995 (online at Ancestry.com):

Name	Walter Morris Straub
Plaintiff / Defendant	Defendant
Date of Action	23 Aug 1922
Place of Action	Bronx, New York, USA
Other Party	Margaret Haslup Straub
Location	Office of Bronx County Clerk
Vol | Pg | File	4 | 202 | 3104

9.  Anon.  Sunday, 6 Jul 1924,  "Court Denies Wife Decree..." Brooklyn Daily Eagle (Brooklyn, NY), p. 8E (online at Newspapers.com):

10.  1930 U.S. Census Every-Name-Index/Images (online at Ancestry.com):  Walter is said to be deceased, and I don't find him anywhere.  Margaret is living with her parents in Baltimore, MD (q.v.), but son, Walter, is not with her.  He's only ten years old.  Has he been sent away to school?

11.  1940 U.S. Census Every-Name-Index/Images (online at Ancestry.com):  can't find Margaret.  Her  mother is deceased and she's not living with her father in Baltimore.  Has she remarried?

12.  Find-a-Grave: Entries (online at findagrave.com):

Name	Walter M Straub
Birth	unknown
Death	1925
Plot	Sec 15-2 Lot 101  Grave 12
Burial	Homewood Cemetery Pittsburgh, Allegheny Co., PA
Inscription	WALTER M. STRAUB 1886 — 1925
Memorial #	91082364

How do we know this is our subject?  "Walter M." is fairly common as a given name and middle initial for STRAUBs.  Secondary sources do attribute this grave (and this birthyear) to our subject.

13.  Public Member Trees (online at Ancestry.com).