Solomon Veniaminovich Shereshevsky (; 1886 – 1 May 1958), also known simply as 'Ш' ('Sh'), 'S.', or Luria's S, was a Soviet journalist and mnemonist active in the 1920s. He was the subject of Alexander Luria's case study The Mind of a Mnemonist (1968). Studies Shereshevsky participated in many behavioral studies, most of them carried out by the neuropsychologist Alexander Luria over a thirty-year time span. He met Luria after an anecdotal event in which he was scolded for not taking any notes while attending a work meeting in the mid-1920s. To the astonishment of everyone there (and to his own astonishment in realizing that others could apparently not do so), he could recall the speech word for word. Throughout his life, Shereshevsky was tasked with memorizing complex mathematical formulas, huge matrices, and even poems in foreign languages that he had never spoken before, all of which he would memorize with meticulous accuracy in a matter of minutes. On the basis of his studies, Luria diagnosed in Shereshevsky an extremely strong version of synaesthesia, fivefold synaesthesia, in which the stimulation of one of his senses produced a reaction in every other. For example, if Shereshevsky heard a musical tone played he would immediately see a colour, touch would trigger a taste sensation, and so on for each of the senses. The images that his synaesthesia produced usually aided him in memorizing. For example, when thinking about numbers he reported: Take the number 1. This is a proud, well-built man; 2 is a high-spirited woman; 3 a gloomy person; 6 a man with a swollen foot; 7 a man with a moustache; 8 a very stout woman—a sack within a sack. As for the number 87, what I see is a fat woman and a man twirling his moustache. The above list of images for digits is consistent with a form of synesthesia (or ideasthesia) known as ordinal linguistic personification but is also related to a well-known mnemonic technique called the number shape system where the mnemonist creates images that physically resemble the digits. Luria did not clearly distinguish between whatever natural ability Shereshevsky might have had and mnemonic techniques like the method of loci and number shapes that "S" described. Shereshevsky also participated in experiments in which he showed that he had control over his body's involuntary functions. From a resting pulse of 70–72, he was able to increase it