Drug-addicted beauty writer Cat Marnell has landed a book deal with Simon & Schuster for her memoir, “How to Murder Your Life.” Marnell, who has been in and out of rehab for her addiction to prescription drugs, famously told us she’d rather “smoke angel dust with her friends” than hold down a full-time job after being fired from Jane Pratt’s Web site, xoJane.com. Now she has chronicled her sexual and narcotic adventures in a book, to include her life as a spoiled rich kid of a psychiatrist and a psychoanalyst and her drug-fueled rise through Condé Nast, xoJane.com and Vice magazine — and that Page Six item. The proposal details her numerous sexual conquests. Aside from four abortions, she recalls getting “choked out by a Park Avenue millionaire kid in a pine grove by the reservoir at 4 a.m.” and “sex in vacant lots in Bushwick with white rappers.” Sources say the deal is worth up to half a million dollars. A rep for S&S confirmed the deal but said, “We don’t comment on author advances.”