Books on Pakistan Affairs are many, but you have to select the books you want to read. Though Imtiaz Shahid's book cover the syllabus to some extant, but you won't be able to find all questions and especially related to the recent developing trends. So try to consult Trek to Pakistan for basics and Ikram Rabbani's Pakistan Affairs for latest trends. Also consult the contemporary affairs digest or articles as questions are also included from contemporary affairs.

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"But screw your courage to the sticking place,
And we'll not fail." _Shakespeare, 'Macbeth')