I assumed Robbie Robertson's sequel to his memoir "Testimony" would cover his collaborative years with Martin Scorsese and then go on to look at his solo career, as well. Whether intentional or because he ran out of time before his death, "Insomnia" is a much more focused work, and practically a love letter to Scorsese and their time together from 1975-1980 as coke-fueled running buddies and roommates. Both are in a dark period in their lives -- Scorsese after the failure of "New York, New York" and a tempestuous fling with Liza Minnelli; Robertson after a split from his wife and from his colleagues in The Band after "The Last Waltz." The musician and the director move in together in Beverly Hills, black out the curtains and start doing prodigious amounts of blow. As in his first book, Robertson writes eloquently about his split life, yearning for his wife and family while chasing after every pretty face he sees. (And, boy, does Robbie have the touch: Genevieve Bujold, Jennifer O'Neill and, for one glorious night, Tuesday Weld. He does fail at wooing Sophia Loren, but, man, the cojones to try!) Robertson calls Scorsese "Maestro" and generously describes their deep friendship while confirming Scorsese's film obsession: The only time the director gets slightly ticked is when Robertson arrives late for nightly screenings at their home. He marches around like a martinet waiting for Robbie to eat so they can start the movie. WATCHING THE MOVIE is not a pastime, it's life itself to Scorsese, and Robertson quickly gets the rush. He and Scorsese hang with everybody from De Niro to Kurosawa. There is one priceless anecdote after another: When Francis Coppola visits and tells Robbie to watch the simmering pasta sauce for an hour but forgets as he goes out on a coke run, I bet I won't be the only one hearing "Jump Into The Fire" and scanning the skies for helicopters. Finally, the partying gets too serious and both Robertson and especially Scorsese come dangerously close to the ledge. The book ends with Robertson's musical work on "Raging Bull," a role he would play in Scorsese's films right up to his death. "Insomnia" is an unexpectedly dishy, but not salacious, peek at the waning years of the New Hollywood era, and Robertson is a genial tour guide to the movies and the madness. The only sadness comes from knowing we will never read a third memoir about his solo albums and his work with Scorsese after "Raging Bull."