Books focusing on the rise of British power in the region and the interplay between various rivals such as the Marathas, Sikhs, Mysore, Afghans etc. The era seems really interesting to me and want to read more.
An excellent overview of the various historical debates about the nature of the 18th century and its historical significance is The Eighteenth Century in India by Seema Alavi.
Also see PJ Marshall, The 18th Century in Indian History: Evolution or revolution.
Also see the various books of the Cambridge History of India, Volume 2, Parts 1-5.
For a broader view of the East India Company that is written in a more "popular" manner, read John Keay, The Honourable Company.
For a more scholarly take on the British Empire as a whole, see The Oxford History of the British Empire, Volume 2.