I am his grandson. Who would you like help finding? Hopefully I can be of assistance.

This might be your Elwin R Cook with his family.

United States Census, 1940
Name Elwin R Cook
Event Type Census
Event Date 1940
Event Place Milwaukie, Milwaukie Election Precinct 2, Clackamas, Oregon, United States
Gender Male
Age 7
Marital Status Single
Race (Original) White
Race White
Relationship to Head of Household (Original) Son
Relationship to Head of Household Son
Birthplace Oregon
Birth Year (Estimated) 1933

Bertha O Cook Head F 44 Nebraska [widow]
Clarence Cook Son M 20 Oregon
Quentin Cook Son M 18 Oregon
Opal Cook Daughter F 16 Oregon
Dorothy Cook Daughter F 15 Oregon
Lillian Cook Daughter F 14 Oregon
Erline Cook Daughter F 13 Oregon
Winnifred Cook Daughter F 11 Oregon
Bertie F Cook Son M 10 Oregon
Elwin R Cook Son M 7 Oregon ***
Betty Lou Cook Daughter F 4 Oregon


1930 United States Federal Census
Name: Bertha O Cook
Birth Year: abt 1896
Gender: Female
Race: White
Birthplace: Nebraska
Marital Status: Married
Relation to Head of House: Wife
Homemaker?: Yes
Home in 1930: Dallas, Polk, Oregon
Map of Home: View Map
Street address: Uglow
Ward of City: 4
House Number in Cities or Towns: 252
Dwelling Number: 202
Family Number: 206
Age at First Marriage: 20
Attended School: No
Able to Read and Write: Yes
Father's Birthplace: Iowa
Mother's Birthplace: Missouri
Able to Speak English: Yes

Bertie F Cook 44 born Nebraska Father: b Canada Mother: b Massachusetts
Bertha O Cook 34 Father: b Iowa Mother : b Missouri
Wesley F Cook 14
Bertrum C Cook 11
Clarence C Cook 10
Elsie E Cook 9
Quentin C Cook 7
Opal E Cook 6
Dorothy B Cook 5
Lillian L Cook 4 [4 5/12]
Erline R Cook 3 [3 1/12]
Winnifred R Cook 1[1 8/12]
Bertie F Cook 0 [5/12]

U.S., Find A Grave Index, 1600s-Current
Name: Bertie Franklin Cook Sr
Birth Date: 31 Mar 1886
Birth Place: Scotia, Greeley County, Nebraska, USA
Death Date: 12 Mar 1935
Death Place: Monmouth, Polk County, Oregon, USA
Cemetery: Dallas Cemetery
Burial or Cremation Place: Dallas, Polk County, Oregon, USA
Has Bio?: N

link to gravestone site:
http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=30212928&ref=acom


United States World War I Draft Registration Cards
Name Bertie Franklin Cook
Event Type Draft Registration
Event Date 1917-1918
Event Place Portland City no 1, Oregon, United States
Gender Male
Nationality United States
Birth Date 31 Mar 1886
Birthplace United States
Wife Bertha O Cook
Lists occ as engineer

Think he married Bertha Opal Blair
BIRTH 28 JUL 1895 • Central City, Merrick, Nebraska, USA
DEATH 31 JAN 1985 • Milwaukie, Clackamas, Oregon, USA


Found this on a number of trees but cannot find reg of marriage to back it up.
Marriage
14 Mar 1916
Bertha Opal Blair (1895–1985)

Oregon, Death Index, 1898-2008
Name Bertha Opa Cook
Age 89
Birth Date 28 Jul 1895
Death Date 31 Jan 1985
Death Place Clackamas
Spouse Bertie
Certificate 85-02127