Dr. Johnson & Mr. Savage is what might be referred to as a microbiography: author Richard Holmes offers full portraits of neither title character, but rather an examination of the short period when the lives of Samuel Johnson - lexicographer, author, poet, and biographical subject extraordinaire - and Richard Savage - poet, rogue, and murderer - converged for a time. Savage, Johnson's first biographical subject himself, made Johnson's acquaintance soon after that young provincial arrived in London, and their companionship lasted for just about two years, until Savage departed for "retirement" in Wales.
Holmes has little to go on: while it's known that Johnson and Savage knew each other, "there are no authenticated letters between the two men, no mention of each other in private journals, not even a single surviving account from an eyewitness of seeing the two men in each other's company." And yet he's done quite a lot with what few scraps of evidence that do exist, creating an interesting web of narrative around a skeleton of knowable facts. While I am afraid that his speculatory meanderings (particularly in the realm of psychology) get the better of him at times (I felt the same about Greenblatt's recent biography of Shakespeare), Holmes generally at least informs the reader of his upcoming leaps, which is comforting if not exculpatory.
As the author notes, the Johnson we meet cavorting with Savage is not the frumpy but majestic old fellow that Boswell has left us, but a young, desperate man out to make his way in the world, captivated by this strange, conflicted, down-and-out poet. It's another side to Johnson that is interesting to find, even within Holmes' imperfect framework.