==This article needs expansion== 
 ...And I propose to do this, using (along with some minor ones) several ru_language sources. In its current state the article is almost totally unsourced, but there’d be no problem in incorporating almost everything that’s already in there into the new, sourced/expanded version. There are some exceptions, though. The following assertions, to my mind, have to be either re-written or dropped altogether, unless some sound arguments are put forward in their defense:  
 * According to tradition, soon after his birth some discord between Lermontov's father and grandmother erupted... - What kind of tradition that is? 
 * As a small boy Lermontov listened to stories about the outlaws of the Volga region, about their great bravery and wild country life. - Well-documented are (later) Lermontov's complaints of having heard too little of Russian folklore in his childhood, being fed mostly with the German fairytales, from his governess Rehmer. Anyway, sourcing wanted.  
 * in 1828, he entered the gymnasium... - That was the Moscow University's elitist boarding school for the nobility children. In 2 years time it was transformed into an (ordinary) gymnasium, and that was exactly what prompted Lermontov's departure. 
 * ...one of his friends, Katerina Khvostovaya... - Khvostova, actually, - but only later, in marriage. She is better known as Yekaterina Sushkova. 
 * A prank pulled by a group of students against one of the professors named Malov brought his time at the University to an end. Several biographers cite this incident as the reason for Mikhail's departure. - At least 4 of my sources tell me otherwise: the Malov incident had no bearing upon Lermontov’s decision to leave the University whatsoever. Participate he did, but hasn’t received any punishment - unlike, say, Hertzen, who's got incarcerated. The 5th source, Mirsky, fails to mention the Malov incident at all.  
 * Young cadet - first poems (section). Dates are wrong. The At that time he began writing poetry... assertion - even more so. He started writing poetry way back in 1827.  
 * Works (section). Lermontov's poetic development was unusual. His earliest unpublished poems that he circulated in manuscript through his friends in the military were pornographic in the extreme, with elements of sadism. - Again, those were not his earliest poems; he started very early and in the University was quite prolific. If his poetic development was indeed strange, then for totally different reasons, but that would be another story. His 'frivolous' verses deserve a mention, but hardly more than that. Some have termed Lermontov's early verse puerile, since, despite his dexterous command of the language, it usually appeals more to adolescents than to adults. - Debatable; needs to be sourced. Besides, what about the earlier 'pornographic in the extreme, with elements of sadism' bid?) 
 * His short poems range from indignantly patriotic pieces... to the pantheistic glorification of living nature... - Looks for me like too narrow a scope. There was some philosophical/metaphysical depth to most of them, too. Besides, along with ‘indignantly patriotic pieces’ there were ‘indignantly unpatriotic’, politically highly provocative ones.  
 Before getting on to the 'Works', though, I'd rather deal with the 'Private Life' sec. -