Originally intended as the second half of last year's 'Relapse', Slim Shady's seventh reportedly evolved into a more "emotionally driven" record worthy of its own title. Charting his, yes, "recovery" from drug addiction and professional self-sabotage, it's potent stuff, only compromised by a number of musically bland tracks and occasional over-sentimentality.

When you're as big a star as Marshall Mathers, there's no trouble finding big names to appear on your latest album. Working with respected hip hop producers including Alex Da Kid Boi-1da, Havoc, and of course, Dr Dre, Eminem also bagged some impressive guest vocalists for Recovery. Yet, for the most part, they add little to the finished product. The Haddaway sampling No Love featuring Lil Wayne comes across as naff, while Rihanna's turn on Love The Way You Lie has none of the presence and attitude of her solo work.

On the other hand, relatively unknown producer Script Shepherd is responsible for hammering, seething highlight Cinderella Man. DJ Khalil is behind some raging, guitar heavy highlights, the best of which is the Pink-featuring Won't Back Down, where Shady offers such comedic lyrical nuggets as "Don't make me introduce you to my power tool, you know the f***ing drill", and "I gave Bruce Wayne a Valium and said settle ya f***ing ass down, I'm ready for combat man/get it, calm batman?" His talent for word play and double entendres is as impressive and, more importantly, as entertaining as ever.

What's interesting is the two sided nature of Recovery. On the one hand, Mathers insistently declares his superiority as well as his new found strength and will, while elsewhere he reveals his vulnerable side. Whether it's mixing heartbreak with rage on 25 to Life or apologetically tearing down his own recent work on Talking To Myself, it's as if he's purposely admitting that his musical persona is just that - a front.

There are points where Shady gets it so right, and others that are almost embarrassing to listen to. Unlike some of his peers, he's aware of himself and the conventions of his genre. He references rappers Lil Wayne, Kanye West, Drake and Flo-Rida, and comments on his own derogatory language with lines like "Why is it when I talk I'm so biased to the hos?" (On Fire). And yet, his need to be controversial sometimes leads him one step beyond tongue in cheek. An ill-advised joke about Michael J. Fox's Parkinson's disease and a description of himself as "a s**t stain on the underwear of life" are among the instances that are neither funny nor clever.

Still, for all his blundering, Eminem's impulsiveness and fallibility are part of his appeal. No, it's a small number of low energy, run of the mill tracks around the midsection that drag this album down. At a total of seventeen tracks long, had a few of these been cut, Recovery might have been the return to form it was billed as.