There was a time, until recently, when one of the country’s most telling contemporary songwriters, Thanassis Papaconstantinou, hovered about like an elusive ghostly entity, a reluctant stage performer and public figure who would connect with fans mostly through his recorded work. But a shift is now being witnessed, as indicated by the artist’s growing frequency of concerts that are erasing the modest figure’s previous reputation as a stage-shy performer. Papaconstantinou, who resides in provincial Larissa, will be in Athens for two shows at the Gagarin Club on Friday and Saturday. Perhaps it has been his widening following – one that has evolved from cult status, to bulging cult status, and now near-mainstream – that has convinced Papaconstantinou, a self-taught musician who has not relied on his music’s earnings for a living, to come out of the woodwork. Until recently, Papaconstantinou worked as a state-employed mechanical engineer in Larissa, but his music’s growing appeal has drawn him closer to song. The latest shows come shortly after a relatively active summer season that included a free open-air concert in the capital and also took him to faraway domestic locations such as Icaria, in the southeast Aegean. Papaconstantinou’s distinctive work has proven hard to label, both because of its unorthodox nature and continual evolution from album to album. He has drifted from an early-period acoustic approach that embodied a peculiar latticework of this country’s old-school popular music and Greek folk to more wayward adventures. The act’s most recent album, «Agrypnia,» released two years ago, melted a previous rigid song structure for less disciplined, mostly instrumental material, inflected with jazz and rock elements. On board were some of the country’s most innovative musicians, who accompany him on stage, and Socrates Malamas, one of the contemporary circuit’s other truly inspired singer-songwriters, as a guest vocalist. Malamas, a seasoned stage performer who knows how to handle a crowd, used to jest, at his own shows, about his close friend and collaborator Papaconstantinou’s stage reluctance. The latter seems to have overcome that now.