AN ESSENTIAL INTRODUCTION TO THE DS SMITH THRILLER SERIES. Phobia is a series of five DS Jason Smith cases he worked on before we met him in the first book 'Smith'. We get insights into what moulded him into the Detective Sergeant we first get a glimpse of in 'Smith'. Smith quickly realizes that police work isn't always cut and dry. Justice is not always black and white; there are many shades of grey in between.