Exclusive: Luke Russert Shares Heartbreaking Moment When He Discovered His Father Tim Russert's Abrupt Demise.

Luke Russert's new memoir, Look For Me There: Grieving My Father, Finding Myself, explores his life as the son of renowned journalist Tim Russert, who passed away suddenly in 2008. After spending eight years at NBC News following his father's death, Luke decided to leave behind his life as a D.C. journalist and travel the world, visiting over 60 countries, an adventure he writes about in the book. In this excerpt, exclusively shared with PEOPLE, Luke recounts the days following his father's death, from hearing the tragic news to writing and delivering his father's eulogy.

While on a family trip to Italy after Luke's graduation from Boston College, Tim Russert flew back to Washington D.C. early to host Meet the Press, a show he had been hosting for over 16 years. Luke and his mother, Maureen Orth, were in Florence preparing for dinner when they received a call that Tim had collapsed in his NBC office. A series of frantic phone calls ensued and they were eventually told what they had feared: Tim had died at just 58, having suffered from a fatal heart attack known as 'the widow maker'.

After receiving confirmation from someone at the hospital, Luke's mother was devastated. Although she had remained in reporter mode until then, tears streamed down her face as she sat back down and motioned for Luke to approach. Despite not feeling pain, Luke felt shocked, as this was the beginning of accepting the horrific reality that their lives would never be the same.

Luke and his mother tried to process the news of Tim's death, and thankfully they were unable to follow updates in real-time as NBC News did not reach Florence, and social media was not as pervasive as it is now. This gave them some time and space to process their emotions without being inundated with constant reminders of their loss. Instead, they spent the hours after Tim's death walking the streets of Florence, trying to steady themselves.

Later that night, Luke finally faced the reality of his loss and cried for all the things he would never experience with his dad, from speaking with him again to watching the Buffalo Bills win a Super Bowl. But despite his sorrow, Luke found inspiration in his father's words and turned to his memoir for guidance on how to write the eulogy. As he wrote, Luke felt a connection to his father's spirit, thinking that perhaps Tim was writing through him.

At the wake, Luke received comfort from seeing the vast crowds who had gathered to honor his father, including the U.S. President. His grief didn't dissipate, but Luke was able to find some solace in the legacy his father had left behind.

The line must be a mile long. My eyes start to well up as I look at the people through the tinted glass. All ages, genders, races, and creeds. It's the American quilt.

We have heard that somebody from the White House was going to pay their respects, but we did not know that it was going to be the president. The sirens from the motorcade are within earshot. The president and Mrs. Bush walk in, escorted by one of my old teachers. President Bush, famous for giving nicknames, has one for me. 'Big Luke! Come here, brother.' He brings me in for a bear hug. 'So sorry, your dad was a good man.'

'Thank you, sir.'

Mom and I pray with them. She holds their hands. They then follow us to the school library to meet the rest of our family. President Bush stays for an hour and greets every single Orth and Russert.

'Thank you for the time, sir,' I say.

'My honor,' says President Bush.

The son of a garbage man, getting a US president to his wake? I can hear Dad mouthing, 'What a country.'

Later, he must rise to the pulpit to eulogize his father.

I walk down the aisle of Holy Trinity Catholic Church in Washington, D.C., step behind Dad's casket. My focus is on Mom and nobody else. So long as she stays strong, I know I'll be fine. The priests have the rest under control.

That is the beauty of the Catholic faith. If nothing else, we know how to do death, following the thousands-year-old script.

At the appropriate time, the priest summonses me to the pulpit for the eulogy. I stare out into a sea of friends, family, and official Washington. In the pews, I see Barack Obama, John McCain, Nancy Pelosi. Joe Biden's face looks especially pained; he is a man all too familiar with grief. The same can be said of Ethel Kennedy, whom I lock eyes with for a brief moment.

And one more event, the public memorial service at the Kennedy Center, where Luke reflects on the world his father has left.

I follow remembrances from Dad's friend Maria Shriver and old boss Mario Cuomo. I see James Carville and Mary Matalin in tears, leading the audience in applause, and then a bear hug comes from Dad's friend Mike Barnicle. My uncle Tony Scozzaro, a gifted guitarist from Buffalo, plays Springsteen's 'Born to Run' as a closing tribute. Then, unexpectedly, Bruce Springsteen himself is piped in via satellite and performs 'ThunderRoad,' Dad's favorite song. That makes me shed my only public tear.

I take a moment backstage to think. Tim Russert died at the height of his career. He died as the nominees for the 2008 presidential election were being settled on after a historic primary season. He died as television media reached its pinnacle, in the last hours before a new digital world. He died just after his son graduated from a Jesuit college. He died days after praying in the Vatican. He died in his favorite season: summer. He died on the Friday before his favorite holiday: Father's Day. The man who wrote books about fatherhood, which caused so many people to reconnect with their dads, actually died on Father's Day weekend.

A fitting ending.

Look For Me There: Grieving My Father, Finding Myself, will be published May 2 by Harper Horizon.