On the Way to a Smile is a series of officially licensed short stories written by FFVII's actual scenario writer Kazushige Nojima that fill in plot information about various characters between the end of FFVII and the start of Advent Children.
Most are only available in Japanese (with numerous unofficial English fan-translations), but apparently Case of Barret was officially released in English with the limited edition version of Advent Children.
There was one other FFVII spin-of novella released - a short story called The Maiden Who Travels the Planet, included with the Japanese FFVII Ultimania Omega guidebook, which is about Aeris's travels in the Lifestream following her death in the game, but this isn't usually believed to actually be canon to the actual storyline (Square Enix themselves have never mentioned or even acknowledged it's existence when referring to FFVII's tie-ins and storyline) and most fans aren't even aware it exists.
If the 'novel' you have is called anything other than these titles, then it's almost definitely an unofficial fanfiction which has not been licensed by Square Enix I'm sorry to say, as the above stories are the only official FFVII tie-in novels available.
More information about On the Way to a Smile and Maiden Who Travels the Planet can be found here: On the Way to a Smile - The Final Fantasy Wiki has more Final Fantasy information than Cid could research (
http://finalfantasy.wikia.com/wiki/On_the_Way_to_a_Smile)
Hoshi wo Meguru Otome - The Final Fantasy Wiki has more Final Fantasy information than Cid could research (
http://finalfantasy.wikia.com/wiki/Hoshi_wo_Meguru_Otome)