The 49-year-old was warned wife Mandy and son Blaine, then aged eight months, would be attacked if he won the 1997 World Championship.
His biography, Me and the Table, is being serialised by the Mirror ahead of the snooker star's 50th birthday.
He explains how the haunting letter was sent to his family home, with the stalker revealing he knew where the couple lived and where Mandy walked their son.
Stephen writes: "If I win the world title this year, the writer promises they will throw acid in my child’s face. The final sentence reads: 'Black ball, black death'."
The snooker ace said the couple tried to ignore the handwritten note, which was flagged to police, but he lost "intensity and focus" fearing what would happen if he won.
Left "rattled" by the poison note, he ended up being beaten by Ken Doherty in the final at 18-12.
Stephen reveals in the book how he had previously been the victim of another stalker who would bombard his manager with photos and letters that became "more threatening and weirder".
The woman, who was later convicted, even wrote a play called The Death of the Snooker Player where main character Stephen is subjected to "all sorts of unspeakable acts" before he is murdered.
Stephen also opens up in the book about the agony his family felt after his son was stillborn following IVF treatment.
He reveals he got a tearful phonecall from his wife after losing at the World Championships in 2003.
Stephen writes: "Now, instead of looking forward to celebrating a new life, we will be planning a funeral."
The pair named the boy Joseph and buried him in a churchyard close to their home – with Stephen carrying the tiny coffin to the funeral in his arms.
Detailing the key events in his life, the snooker star also tells how he fell for Lauren, a woman 20 years younger than him, after meeting at various snooker events and becoming friendly.
He writes: "People talk about mid-life crisis. But I met someone else and it knocked me for six."
The seven-times world champ then goes into the fallout of his new relationship, and having to call time on his marriage to Mandy.
Stephen writes: "I stay with friends and family while Mandy and I attempt to patch up our marriage. We agree to give it another go. I’m riddled with guilt about the whole thing, but I’m also in love with someone else."
He describes how they tried to salvage the relationship before he realised Mandy can't trust him anymore and eventually they both agreed the marriage is over.
The dad-of-two says telling his sons Blaine, now 21, and Carter, 13, he had to leave was one of the lowest moments of his life.
He writes: "Carter is upset; Blaine becomes very quiet, just like I did when I found out about my parents splitting up.
"It’s horrible, and I feel like the worst person in the world."
The successful snooker player writes about the financial and emotional costs of leaving his wife and setting up an eventual home with Lauren.
He describes the three years between moving out of his Scottish family home and getting the divorce finalised as "the most stressful of my life".
But he concludes that four years on from the breakup of his marriage he is still happily with Lauren and his regrets surround his sons.
The boys were affected by the divorce, he writes, but he adds he is proud of them and credits Mandy for bringing them up well.
Nicknamed "The Great One" and "The Golden Boy", he is regarded as one of the greatest players to ever grace the sport.
At the age of just 16 he became the youngest ever professional snooker player after winning the World Amateur Championship twice – first at 14 and then again two years later.
Earlier this year we reported how the legend hit out at claims he had written a, differently titled, autobiography – after fans were able to pre-order copies.
Source: Read Full Article