This book is simply a must have for anyone seriously interested in Sikh history. It contains fresh translations of Persian sources on Sikhs and is particularly useful for gaining a better understanding of Banda Singh Bahadur's revolution, as the accounts of many contemporaries are included.
Despite my feeling that Mr. Grewal is a bit too close to W.H McLeod for comfort (his "older brother" apparently), the book delivered. However I note that Grewal doesn't miss an opportunity to highlight his own caste in his own personal commentary in a very unKhalsa like fashion. Still, seeing as it is difficult if not impossible to obtain all of these translations from other sources, your library on Sikhs will be incomplete without this book.