Paul O'Brien Sr. departed this world to be with the Lord the morning of August 9, 2013 in San Mateo, California. Paul was born on December 27, 1929 to Raphael and Isabel O'Brien in Pittsburgh, Pa. Paul received his undergraduate degree in Chemistry from the University of Pittsburgh. He went on to receive a PHD from University of Florida in 1967 in Physical Organic Chemistry being awarded a National Graduate Fellowship. He served in the Army during the Korean conflict. He lived in Northern California for many years and was employed as a Chemistry professor with the West Valley-Mission Community College District. He is survived by six children; Paul O'Brien Jr., Ellen O'Brien-Garcia, Carol Davis, Kevin O'Brien, Sharon Ibrahim, John O'Brien, and their mother Betty J. Cunningham O'Brien; sixteen grandchildren-two deceased, and three great-grandchildren. He also leaves behind his ex-wife Catherine Shea, who he married in 1989. He moved to Hawaii in 1999 and has been living in Kailua-Kona for the past 14 years. He is a member of St. Michael's Catholic Church in Kailua-Kona. He paddled with the Kai Opua Canoe Club and the Keauhow Canoe Club. He could always be seen walking his beloved dog Maile around town. He loved teaching Chemistry and while in Northern California teaching for a semester, he suffered a stroke this past April. The stroke was complicated by different infections, which caused his declining condition. Paul is with his family in heaven, his sister June Burke (O'Brien), his brother-in-law Bill Burke, his "brother" John O'Brien, his mother and father, all his aunts and uncles but most especially our beloved Shane and one of his best friends from the bay area, Ron Smith. He will be missed by all his friends and family and especially by his dog, Maile. Viewing will be Sunday 8/11/2013 at 12:30pm Crippen &Flynn, 1111Alameda de las Pulgas, Belmont, CA. Paul will be cremated at Irvington Memorial Cemetery, and returned to Hawaii. Service will be at St. Michael's Church Kailua-Kona, followed by the scattering of ashes by his Canoe club off the coast of Kailua-Kona at a future date.