If you"ve got the key to literary success, it is a risky business indeed to make an abrupt change of subject that may lose you some readers. Has Alexander McCall Smith done this with Friends, Lovers, Chocolate? After all, his much-loved No. 1 Ladies’ Detective Agency Series has won him a legion of admirers, with its vividly evoked African settings, quirky plotting and (most of all) his likeable, "generously proportioned" sleuth Precious Ramotswe. These gentle, indulgently enjoyable books were quite unlike anything else being published today, and found a ready audience. But McCall Smith, not content to rest on his laurels, produced The Sunday Philosophy Club, with a new female detective, the philosopher Isabel Dalhousie. This was a very different kettle of fish, with an Edinburgh setting replacing sultry Botswana, and more philosophical concerns replacing the homely adages. The book was a success, without seducing readers in quite the numbers that the previous series had done. And now we have the second outing for Isabel Dalhousie -- and Friends, Lovers, Chocolate bids fair to cement McCall Smith"s new heroine in readers’ affections – though she’ll never replace Precious. Isabel is trying to deal with her uncertain feelings for an attractive young man, Jamie, who is planning to marry her niece, Cat. Things become even more complicated when Cat takes an Italian vacation and asks Isabel to look after her delicatessen. Isabel finds out that one of the customers has had a heart transplant, and seems to be accessing memories that he is convinced belong to another person. As Isabel digs deeper, things suddenly become dangerous. The appeal of the new book is (like its predecessor) more to the mind than the emotions, but it"s none the worse for that. McCall Smith"s brittle dialogue and situations are as entertainingly off-kilter as ever, and even fans of the ample Precious should put this on their lists. --Barry Forshaw