Professor George Andrews assessed:

The most interesting item in this box was a manuscript of more than one hundred pages in Ramanujan's distinctive handwriting which contains over six hundred mathematical formulae listed one after the other without proof. It is my contention that this manuscript, or notebook, was written during the last year of Ramanujan's life after his return to India from England. My evidence for this assertion is all indirect; in the words of Stephen Leacock, 'It is what we call circumstantial evidence - the same that people are hanged for'.

While it is impossible to categorize the various formulas completely, a rough approximation of its contents is the following:

q-series and related topics including mock θ-functions: 60%
Modular equations and relation, singular moduli: 30%
Integrals, Dirichlet series, congruences, asymptotics, misc.: 10%

I give only this rough break down because of the chaotic nature of this manuscript. On many pages, there are fragments of numerical computations and infinite series running off in all directions. It may be possible eventually to make sense out of some of these pages; if so, the above percentage breakdown may change. …

In any event, it is clear that q-series investigations make up the bulk of the work in the Lost Notebook. Indeed I count about 380 formulae that I consider to belong more to q-series than to modular relations or other topics.