  This is the first draft of a book about higher categories approached by
iterating Segal's method, as in Tamsamani's definition of $n$-nerve and
Pelissier's thesis. If $M$ is a tractable left proper cartesian model category,
we construct a tractable left proper cartesian model structure on the category
of $M$-precategories. The procedure can then be iterated, leading to model
categories of $(\infty, n)$-categories.
