As you may know, Rev. Burns was the minister who took Rev. Robert Murray Mc'Cheyne's pulpit in Dundee in 1839, while Rev. Mc'Cheyne traveled to Israel. Under Rev. Burns' ministry, a great revival began, and much of the first half of the book is an account of that revival.
The book is very interesting and encouraging, and I would highly recommend it (though I haven't actually finished it--I have yet to read the part about Rev. Burns' missionary work in China). You can read it for free on Google Books here.
An especially nice quote, from a letter Rev. Burns wrote to his sister:
The great fundamental error then, as far as I can see, in the economy of the Christian life...is that of having too few and too short periods of solemn retirement with our gracious Father and his adorable Son Jesus Christ...
The communion of the saints in Christian converse is indeed important, nay, indispensable to the growth of the new man when it can be obtained, but when is it sweet and soul-reviving but when each brings out into the common store something of the heavenly food which he has been gathering in the closet?